Attention deficit hyperactivity disorder (
ADHD or
AD/HD or
ADD) is a
developmental disorderDevelopmental disorders occur at some stage in a child's development, often retarding the development. These may include,psychological or physical disorders. The disorder is an impairment in the normal development of motor or cognitive skills that are developed before age 18 in which they are...
. It is primarily characterized by "the co-existence of attentional problems and
hyperactivity, with each behavior occurring infrequently alone" and symptoms starting before seven years of age.
ADHD is the most commonly studied and diagnosed psychiatric disorder in children, affecting about 3 to 5 percent of children globally and diagnosed in about 2 to 16 percent of school aged children. It is a
chronicA chronic disease is a disease or other human health condition that is persistent or long-lasting in nature. The term chronic is usually applied when the course of the disease lasts for more than three months. Common chronic diseases include asthma, cancer, diabetes and HIV/AIDS.In medicine, the...
disorder with 30 to 50 percent of those individuals diagnosed in childhood continuing to have symptoms into adulthood. Adolescents and adults with ADHD tend to develop coping mechanisms to compensate for some or all of their impairments. It is estimated that 4.7 percent of American adults live with ADHD. Standardized rating scales such as
WHOThe World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
's
Adult ADHD Self-Report ScaleThe Adult ADHD Self-Report Scale Symptom Checklist is a self-reported questionnaire used to assist in the diagnosis of adult ADHD.-Background:...
can be used for ADHD screening and assessment of the disorder's symptoms' severity.
ADHD is diagnosed two to four times more frequently in boys than in girls, though studies suggest this discrepancy may be partially due to subjective bias of referring teachers. ADHD management usually involves some combination of medications, behavior modifications, lifestyle changes, and counseling. Its symptoms can be difficult to differentiate from other disorders, increasing the likelihood that the diagnosis of ADHD will be missed. Additionally, most clinicians have not received formal training in the assessment and treatment of ADHD, particularly in adult patients.
ADHD and its diagnosis and treatment have been considered controversial since the 1970s. The controversies have involved clinicians, teachers, policymakers, parents and the media. Topics include the actuality of the disorder, its causes, and the use of stimulant medications in its treatment. Most healthcare providers accept that ADHD is a genuine disorder with debate in the scientific community centering mainly around how it is diagnosed and treated. The
American Medical AssociationThe American Medical Association , founded in 1847 and incorporated in 1897, is the largest association of medical doctors and medical students in the United States.-Scope and operations:...
concluded in 1998 that the diagnostic criteria for ADHD are based on extensive research and, if applied appropriately, lead to the diagnosis with high
reliabilityIn statistics, inter-rater reliability, inter-rater agreement, or concordance is the degree of agreement among raters. It gives a score of how much homogeneity, or consensus, there is in the ratings given by judges. It is useful in refining the tools given to human judges, for example by...
.
Classification
ADHD may be seen as one or more continuous traits found normally throughout the general population. It is a
developmental disorderDevelopmental disorders occur at some stage in a child's development, often retarding the development. These may include,psychological or physical disorders. The disorder is an impairment in the normal development of motor or cognitive skills that are developed before age 18 in which they are...
in which certain traits such as impulse control lag in development. Using
magnetic resonance imagingMagnetic resonance imaging , nuclear magnetic resonance imaging , or magnetic resonance tomography is a medical imaging technique used in radiology to visualize detailed internal structures...
of the prefrontal cortex, this developmental lag has been estimated to range from 3 to 5 years. However, the definition of ADHD is based on behaviour and it does not imply a neurological disease. ADHD is classified as a disruptive behavior disorder along with
oppositional defiant disorderOppositional defiant disorder is a diagnosis described by the Diagnostic and Statistical Manual of Mental Disorders as an ongoing pattern of disobedient, hostile and defiant behavior toward authority figures which goes beyond the bounds of normal childhood behavior...
,
conduct disorderConduct disorder is psychological disorder diagnosed in childhood that presents itself through a repetitive and persistent pattern of behavior in which the basic rights of others or major age-appropriate norms are violated...
and
antisocial disorderAntisocial personality disorder is described by the American Psychiatric Association's Diagnostic and Statistical Manual, fourth edition , as an Axis II personality disorder characterized by "...a pervasive pattern of disregard for, and violation of, the rights of others that begins in childhood...
.
ADHD has three subtypes:
- Predominantly hyperactive-impulsive
- Most symptoms (six or more) are in the hyperactivity-impulsivity categories.
- Fewer than six symptoms of inattention are present, although inattention may still be present to some degree.
- Predominantly inattentive
ADHD predominantly inattentive is one of the three subtypes of Attention-deficit hyperactivity disorder . While ADHD-PI is sometimes still called "attention deficit disorder" by the general public, these older terms were formally changed in 1994 in the new Diagnostic and Statistical Manual of...
- The majority of symptoms (six or more) are in the inattention category and fewer than six symptoms of hyperactivity-impulsivity are present, although hyperactivity-impulsivity may still be present to some degree.
- Children with this subtype are less likely to act out or have difficulties getting along with other children. They may sit quietly, but they are not paying attention to what they are doing. Therefore, the child may be overlooked, and parents and teachers may not notice symptoms of ADHD.
- Combined hyperactive-impulsive and inattentive
- Six or more symptoms of inattention and six or more symptoms of hyperactivity-impulsivity are present.
- Most children with ADHD have the combined type.
Signs and symptoms
Inattention, hyperactivity, and impulsivity are the key behaviors of ADHD. The symptoms of ADHD are especially difficult to define because it is hard to draw the line at where normal levels of inattention, hyperactivity, and impulsivity end and clinically significant levels requiring intervention begin. To be diagnosed with ADHD, symptoms must be observed in two different settings for six months or more and to a degree that is greater than other children of the same age.
The symptom categories of ADHD in children yield three potential classifications of ADHD—predominantly inattentive type, predominantly hyperactive-impulsive type, or combined type if criteria for both subtypes are met:
Predominantly inattentive type symptoms may include:
- Be easily distracted, miss details, forget things, and frequently switch from one activity to another
- Have difficulty maintaining focus on one task
- Become bored with a task after only a few minutes, unless doing something enjoyable
- Have difficulty focusing attention on organizing and completing a task or learning something new or trouble completing or turning in homework assignments, often losing things (e.g., pencils, toys, assignments) needed to complete tasks or activities
- Not seem to listen when spoken to
- Daydream, become easily confused, and move slowly
- Have difficulty processing information as quickly and accurately as others
- Struggle to follow instructions.
Predominantly hyperactive-impulsive type symptoms may include:
- Fidget and squirm in their seats
- Talk nonstop
- Dash around, touching or playing with anything and everything in sight
- Have trouble sitting still during dinner, school, and story time
- Be constantly in motion
- Have difficulty doing quiet tasks or activities.
and also these manifestations primarily of impulsivity:
- Be very impatient
- Blurt out inappropriate comments, show their emotions without restraint, and act without regard for consequences
- Have difficulty waiting for things they want or waiting their turns in games
Most people exhibit some of these behaviors, but not to the degree where such behaviors significantly interfere with a person's work, relationships, or studies—and in the absence of significant interference or impairment, a diagnosis of ADHD is normally not appropriate. The core impairments are consistent even in different cultural contexts.
Symptoms may persist into adulthood for up to half of children diagnosed with ADHD. This rate is difficult to estimate, as there are no official diagnostic criteria for ADHD in adults. ADHD in adults remains a clinical diagnosis. The signs and symptoms may differ from those during childhood and adolescence due to the adaptive processes and avoidance mechanisms learned during the process of socialisation.
A 2009 study found that children with ADHD move around a lot because it helps them stay alert enough to complete challenging tasks.
Comorbid disorders
Inattention and "hyperactive" behavior are not the only problems in children with ADHD. ADHD exists alone in only about 1/3 of the children diagnosed with it. Such combinations can greatly complicate diagnosis and treatment. Many co-existing conditions require other courses of treatment and should be diagnosed separately instead of being grouped in the ADHD diagnosis.
Anxiety and depression are some of the disorders which can accompany ADHD. Academic studies and research in private practice suggest that depression in ADHD appears to be increasingly prevalent in children as they get older, with a higher rate of increase in girls than in boys, and to vary in prevalence with the subtype of ADHD. Where a mood disorder complicates ADHD it would be prudent to treat the mood disorder first, but parents of children who have ADHD often wish to have the ADHD treated first, because the response to treatment is quicker.
Some of the associated conditions are:
- Oppositional defiant disorder
Oppositional defiant disorder is a diagnosis described by the Diagnostic and Statistical Manual of Mental Disorders as an ongoing pattern of disobedient, hostile and defiant behavior toward authority figures which goes beyond the bounds of normal childhood behavior...
(35%) and conduct disorderConduct disorder is psychological disorder diagnosed in childhood that presents itself through a repetitive and persistent pattern of behavior in which the basic rights of others or major age-appropriate norms are violated...
(26%) which both are characterized by antisocial behaviors such as stubbornness, aggression, frequent temper tantrums, deceitfulness, lying, or stealing, inevitably linking these comorbid disorders with antisocial personality disorderAntisocial personality disorder is described by the American Psychiatric Association's Diagnostic and Statistical Manual, fourth edition , as an Axis II personality disorder characterized by "...a pervasive pattern of disregard for, and violation of, the rights of others that begins in childhood...
(ASPD); about half of those with hyperactivity and ODD or CD develop ASPD in adulthood.
- Borderline personality disorder
Borderline personality disorder is a personality disorder described as a prolonged disturbance of personality function in a person , characterized by depth and variability of moods.The disorder typically involves unusual levels of instability in mood; black and white thinking, or splitting; the...
, which was according to a study on 120 female psychiatric patients diagnosed and treated for BPD associated with ADHD in 70 percent of those cases.
- Primary disorder of vigilance
In modern psychology, vigilance, also termed sustained attention, is defined as the ability to maintain attention and alertness over prolonged periods of time. The study of vigilance has expanded since the 1940s mainly due to the increased interaction of people with machines for applications...
, which is characterized by poor attention and concentration, as well as difficulties staying awake. These children tend to fidget, yawn and stretch and appear to be hyperactive in order to remain alert and active.
- Mood disorder
Mood disorder is the term designating a group of diagnoses in the Diagnostic and Statistical Manual of Mental Disorders classification system where a disturbance in the person's mood is hypothesized to be the main underlying feature...
s. Boys diagnosed with the combined subtype have been shown likely to suffer from a mood disorder.
- Bipolar disorder
Bipolar disorder or bipolar affective disorder, historically known as manic–depressive disorder, is a psychiatric diagnosis that describes a category of mood disorders defined by the presence of one or more episodes of abnormally elevated energy levels, cognition, and mood with or without one or...
. As many as 25 percent of children with ADHD have bipolar disorder. Children with this combination may demonstrate more aggression and behavioral problems than those with ADHD alone.
- Anxiety disorder
Anxiety disorder is a blanket term covering several different forms of abnormal and pathological fear and anxiety. Conditions now considered anxiety disorders only came under the aegis of psychiatry at the end of the 19th century. Gelder, Mayou & Geddes explains that anxiety disorders are...
, which has been found to be common in girls diagnosed with the inattentive subtype of ADHD.
- Obsessive-compulsive disorder
Obsessive–compulsive disorder is an anxiety disorder characterized by intrusive thoughts that produce uneasiness, apprehension, fear, or worry, by repetitive behaviors aimed at reducing the associated anxiety, or by a combination of such obsessions and compulsions...
. OCD is believed to share a genetic component with ADHD and shares many of its characteristics.
In adults
Researchers found that 60 percent of the children diagnosed with ADHD continue having symptoms well into adulthood. Many adults, however, remain untreated. Untreated adults with ADHD often have chaotic lifestyles, may appear to be disorganized and may rely on non-prescribed drugs and alcohol to get by. They often have such associated psychiatric
comorbiditiesIn medicine, comorbidity is either the presence of one or more disorders in addition to a primary disease or disorder, or the effect of such additional disorders or diseases.- In medicine :...
as
depressionMajor depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...
,
anxiety disorderAnxiety disorder is a blanket term covering several different forms of abnormal and pathological fear and anxiety. Conditions now considered anxiety disorders only came under the aegis of psychiatry at the end of the 19th century. Gelder, Mayou & Geddes explains that anxiety disorders are...
,
substance abuseA substance-related disorder is an umbrella term used to describe several different conditions associated with several different substances .A substance related disorder is a condition in which an individual uses or abuses a...
, or a
learning disabilityLearning disability is a classification including several disorders in which a person has difficulty learning in a typical manner, usually caused by an unknown factor or factors...
. A diagnosis of ADHD may offer adults insight into their behaviors and allow patients to become more aware and seek help with coping and treatment strategies. There is controversy amongst some experts on whether ADHD persists into adulthood. Recognized as occurring in adults in 1978, it is currently not addressed separately from ADHD in childhood. Obstacles that clinicians face when assessing adults who may have ADHD include developmentally inappropriate diagnostic criteria, age-related changes, comorbidities and the possibility that high intelligence or situational factors can mask ADHD.
Cause
The specific causes of ADHD are not known. There are, however, a number of factors that may contribute to, or exacerbate ADHD. They include genetics, diet and the social and physical environments.
Genetics
Twin studiesTwin studies help disentangle the relative importance of environmental and genetic influences on individual traits and behaviors. Twin research is considered a key tool in behavioral genetics and related fields...
indicate that the disorder is highly heritable and that genetics are a factor in about 75 percent of all cases. Hyperactivity also seems to be primarily a genetic condition; however, other causes have been identified.
Researchers believe that a large majority of ADHD cases arise from a combination of various genes, many of which affect
dopamineDopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...
transporters. Candidate genes include
α2A adrenergic receptorThe alpha-2A adrenergic receptor , also known as ADRA2A, is an alpha-2 adrenergic receptor, and also denotes the human gene encoding it.-Role in Central Nervous System:...
,
dopamine transporterThe dopamine transporter is a membrane-spanning protein that pumps the neurotransmitter dopamine out of the synapse back into cytosol, from which other transporters sequester DA and NE into vesicles for later storage and release...
,
dopamine receptorDopamine receptors are a class of metabotropic G protein-coupled receptors that are prominent in the vertebrate central nervous system . The neurotransmitter dopamine is the primary endogenous ligand for dopamine receptors....
s
D2Dopamine receptor D2, also known as D2R, is a protein that, in humans, is encoded by the DRD2 gene.- Function :This gene encodes the D2 subtype of the dopamine receptor. This G protein-coupled receptor inhibits adenylyl cyclase activity...
/
D3D dopamine receptor is a protein that in humans is encoded by the DRD3 gene.This gene encodes the D3 subtype of the dopamine receptor. The D3 subtype inhibits adenylyl cyclase through inhibitory G-proteins. This receptor is expressed in phylogenetically older regions of the brain, suggesting that...
, dopamine beta-hydroxylase
monoamine oxidaseL-Monoamine oxidases are a family of enzymes that catalyze the oxidation of monoamines. They are found bound to the outer membrane of mitochondria in most cell types in the body. The enzyme was originally discovered by Mary Bernheim in the liver and was named tyramine oxidase...
A,
catecholamineCatecholamines are molecules that have a catechol nucleus consisting of benzene with two hydroxyl side groups and a side-chain amine. They include dopamine, as well as the "fight-or-flight" hormones adrenaline and noradrenaline released by the adrenal medulla of the adrenal glands in response to...
-methyl transferase, serotonin transporter promoter (SLC6A4),
5HT2A receptorThe mammalian 5-HT2A receptor is a subtype of the 5-HT2 receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor . This is the main excitatory receptor subtype among the GPCRs for serotonin , although 5-HT2A may also have an inhibitory effect on certain areas such...
,
5HT1B receptor5-hydroxytryptamine receptor 1B also known as the 5-HT1B receptor is a protein that in humans is encoded by the HTR1B gene. The 5-HT1B receptor is a 5-HT receptor subtype.-Tissue distribution and function:...
, the 10-repeat allele of the DAT1 gene, the 7-repeat allele of the DRD4 gene, and the dopamine beta hydroxylase gene (DBH TaqI). A common variant of a gene called
LPHN3Latrophilin-3 is a protein that in humans is encoded by the LPHN3 gene.- Function :This gene encodes a member of the latrophilin subfamily of G protein-coupled receptors . Latrophilins may function in both cell adhesion and signal transduction...
is estimated to be responsible for about 9% of the incidence of ADHD, and ADHD cases where this gene is present are particularly responsive to stimulant medication.
Evolutionary theories
The hunter vs. farmer theory is a hypothesis proposed by author
Thom HartmannThom Hartmann is an American radio host, author, former psychotherapist and entrepreneur, and progressive political commentator. His nationally-syndicated radio show, The Thom Hartmann Program, airs in the United States and has 2.75 million listeners a week...
about the origins of ADHD. The theory proposes that hyperactivity may be an adaptive behavior in pre-modern humans and that those with ADHD retain some of the older "hunter" characteristics associated with early pre-agricultural human society. According to this theory, individuals with ADHD may be more adept at searching and seeking and less adept at staying put and managing complex tasks over time. Further evidence showing hyperactivity may be evolutionarily beneficial was put forth in 2006 in a study which found it may carry specific benefits for certain forms of ancient society. In these societies, those with ADHD are hypothesized to have been more proficient in tasks involving risk or competition (i.e. hunting, mating rituals, etc.). A genetic variant associated with ADHD (DRD4 48bp VNTR 7R allele), has been found to be at higher frequency in more nomadic populations and those with more of a history of migration. Consistent with this, another group of researchers observed that the health status of nomadic
AriaalThe Ariaal are northern Kenyan pastoralists.They claim descent from cattle-owning Samburu who captured significant herds of camels and learnt how to manage them from their eastern neighbours, the Rendille. This led them to adopt the Rendille culture, language, and other Rendille practices, such as...
men was higher if they had the ADHD associated genetic variant (7R alleles). However in recently sedentary (non-nomadic)
AriaalThe Ariaal are northern Kenyan pastoralists.They claim descent from cattle-owning Samburu who captured significant herds of camels and learnt how to manage them from their eastern neighbours, the Rendille. This led them to adopt the Rendille culture, language, and other Rendille practices, such as...
those with 7R alleles seemed to have slightly worse health.
Environmental
Twin studies to date have suggested that approximately 9 to 20 percent of the variance in hyperactive-impulsive-inattentive behavior or ADHD symptoms can be attributed to nonshared environmental (nongenetic) factors. Environmental factors implicated include alcohol and tobacco smoke exposure during pregnancy and environmental exposure to
leadLead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
in very early life. The relation of smoking to ADHD could be due to nicotine causing
hypoxiaHypoxia, or hypoxiation, is a pathological condition in which the body as a whole or a region of the body is deprived of adequate oxygen supply. Variations in arterial oxygen concentrations can be part of the normal physiology, for example, during strenuous physical exercise...
(lack of oxygen) to the
fetusA fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...
in utero. It could also be that women with ADHD are more likely to smoke and therefore, due to the strong genetic component of ADHD, are more likely to have children with ADHD. Complications during pregnancy and birth—including
premature birthIn humans preterm birth refers to the birth of a baby of less than 37 weeks gestational age. The cause for preterm birth is in many situations elusive and unknown; many factors appear to be associated with the development of preterm birth, making the reduction of preterm birth a challenging...
—might also play a role.
ADHD patients have been observed to have higher than average rates of head injuries; however, current evidence does not indicate that head injuries are the cause of ADHD in the patients observed. Infections during pregnancy, at birth, and in early childhood are linked to an increased risk of developing ADHD. These include various viruses (measles, varicella, rubella, enterovirus 71) and streptococcal bacterial infection.
A 2007 study linked the
organophosphateAn organophosphate is the general name for esters of phosphoric acid. Phosphates are probably the most pervasive organophosphorus compounds. Many of the most important biochemicals are organophosphates, including DNA and RNA as well as many cofactors that are essential for life...
insecticide
chlorpyrifosChlorpyrifos is a crystalline organophosphate insecticide that inhibits acetylcholinesterase and is used to control insect pests. It is known by many trade names...
, which is used on some fruits and vegetables, with delays in learning rates, reduced physical coordination, and behavioral problems in children, especially ADHD.
A 2010 study found that pesticide exposure is strongly associated with an increased risk of ADHD in children. Researchers analyzed the levels of organophosphate residues in the urine of more than 1,100 children aged 8 to 15 years old, and found that those with the highest levels of dialkyl phosphates, which are the breakdown products of organophosphate pesticides, also had the highest incidence of ADHD. Overall, they found a 35 percent increase in the odds of developing ADHD with every 10-fold increase in urinary concentration of the pesticide residues. The effect was seen even at the low end of exposure: children who had any detectable, above-average level of pesticide metabolite in their urine were twice as likely as those with undetectable levels to record symptoms of ADHD.
Three government-funded longitudinal studies from 2010 and 2011 examined environmental exposure to
organophosphateAn organophosphate is the general name for esters of phosphoric acid. Phosphates are probably the most pervasive organophosphorus compounds. Many of the most important biochemicals are organophosphates, including DNA and RNA as well as many cofactors that are essential for life...
pesticides between pregnancy and grade school. Although the studies varied in techniques to measure pesticide exposure, they reached similar conclusions. Children exposed to higher levels of organophosphates during pregnancy were more likely to have lower IQs and problems focusing or solving problems. One study suggested that genetics play a strong role in whether exposure to organophosphates causes damage. Two studies found higher rates of ADHD diagnosis among children exposed to higher levels of organophosphate pesticides.
Diet
A study published in The Lancet in 2007 found a link between children’s ingestion of many commonly used artificial food colors, the preservative
sodium benzoateSodium benzoate has the chemical formula NaC6H5CO2; it is a widely used food preservative, with E number E211. It is the sodium salt of benzoic acid and exists in this form when dissolved in water. It can be produced by reacting sodium hydroxide with benzoic acid.-Uses:Sodium benzoate is a...
and hyperactivity. In response to these findings, the British government took prompt action. According to the
Food Standards AgencyThe Food Standards Agency is a non-ministerial government department of the Government of the United Kingdom. It is responsible for protecting public health in relation to food throughout the United Kingdom and is led by a board appointed to act in the public interest...
, the food regulatory agency in the UK, food manufacturers are being encouraged to voluntarily phase out the use of most artificial food colors by the end of 2009. Following the FSA’s actions, the European Commission ruled that any food products containing the “Southampton Six” (The contentious colourings are: sunset yellow FCF (E110), quinoline yellow (E104), carmoisine (E122), allura red (E129), tartrazine (E102) and ponceau 4R (E124)) must display warning labels on their packaging by 2010. In the US, little has been done to curb food manufacturer’s use of specific food colors, despite the new evidence presented by the Southampton study. However, the existing US Food Drug and Cosmetic Act had already required that artificial food colors be approved for use, that they must be given FD&C numbers by the FDA, and the use of these colors must be indicated on the package. This is why food packaging in the USA may state something like: "Contains FD&C Red #40." As of March 2011, the FDA was evaluating the scientific evidence of a link between dyes and ADHD; a preliminary analysis found there was no link.
Social
The
World Health OrganizationThe World Health Organization is a specialized agency of the United Nations that acts as a coordinating authority on international public health. Established on 7 April 1948, with headquarters in Geneva, Switzerland, the agency inherited the mandate and resources of its predecessor, the Health...
states that the diagnosis of ADHD can represent family dysfunction or inadequacies in the educational system rather than individual psychopathology. Other researchers believe that relationships with caregivers have a profound effect on attentional and self-regulatory abilities. A study of foster children found that a high number of them had symptoms closely resembling ADHD. Researchers have found behavior typical of ADHD in children who have suffered violence and emotional abuse. Furthermore, Complex Post Traumatic Stress Disorder can result in attention problems that can look like ADHD. ADHD is also considered to be related to
sensory integration dysfunctionSensory integration dysfunction is a neurological disorder characterized by a neurological sensory integration deficit. The more current diagnostic nosology uses the term sensory processing disorder to describe this condition....
.
A 2010 article by CNN suggests that there is an increased risk for internationally adopted children to develop mental health disorders, such as ADHD and ODD. The risk may be related to the length of time the children spent in an orphanage, especially if they were neglected or abused. Many of these families who adopted the affected children feel overwhelmed and frustrated, since managing their children may entail more responsibilities than originally anticipated. The adoption agencies may be aware of the child's behavioral history, but decide to withhold the information prior to the adoption. This in turn has resulted in some parents suing adoption agencies, in the abuse of children, and even in the relinquishment of the child.
Neurodiversity
Proponents of the neurodiversity theory assert that atypical (neurodivergent) neurological development is a normal human difference that is to be tolerated and respected just like any other human difference. Social critics argue that while biological factors may play a large role in difficulties with sitting still in class and/or concentrating on schoolwork in some children, these children could have failed to integrate others' social expectations of their behavior for a variety of other reasons. As genetic research into ADHD proceeds, it may become possible to integrate this information with the neurobiology in order to distinguish disability from varieties of normal or even exceptional functioning in people along the same spectrum of attention differences.
Social construct theory of ADHD
Social construction theory states that it is societies that determine where the line between normal and abnormal behavior is drawn. Thus society members including physicians, parents, teachers, and others are the ones who determine which diagnostic criteria are applied and thus determine the number of people affected. This is exemplified in the fact that the DSM IV arrives at levels of ADHD three to four times higher than those obtained with use of the ICD 10.
Thomas SzaszThomas Stephen Szasz is a psychiatrist and academic. Since 1990 he has been Professor Emeritus of Psychiatry at the State University of New York Health Science Center in Syracuse, New York. He is a well-known social critic of the moral and scientific foundations of psychiatry, and of the social...
, a proponent of this theory, has argued that ADHD was "invented and not discovered."
Low arousal theory
According to the low arousal theory, people with ADHD need excessive activity as self-stimulation because of their state of abnormally low
arousalArousal is a physiological and psychological state of being awake or reactive to stimuli. It involves the activation of the reticular activating system in the brain stem, the autonomic nervous system and the endocrine system, leading to increased heart rate and blood pressure and a condition of...
. The theory states that those with ADHD cannot self-moderate, and their attention can only be gained by means of environmental
stimuliIn physiology, a stimulus is a detectable change in the internal or external environment. The ability of an organism or organ to respond to external stimuli is called sensitivity....
, which in turn results in disruption of attentional capacity and an increase in hyperactive behaviour.
Without enough stimulation coming from the environment, an ADHD child will create it him or herself by walking around,
fidgetingFidgeting is the act of moving about restlessly. Fidgeting may be a result of nervousness, agitation, boredom or a combination of these. It may be a result of genes and is often an unconscious act. Fidgeting may involve playing with one's fingers, hair, or items of clothing. A common act of...
, talking, etc. This theory also explains why stimulant medications have high success rates and can induce a calming effect at therapeutic dosages among children with ADHD. It establishes a strong link with scientific data that ADHD is connected to abnormalities with the neurochemical dopamine and a powerful link with low-stimulation PET scan results in ADHD subjects.
Pathophysiology
The
pathophysiologyPathophysiology is the study of the changes of normal mechanical, physical, and biochemical functions, either caused by a disease, or resulting from an abnormal syndrome...
of ADHD is unclear and there are a number of competing theories. Research on children with ADHD has shown a general reduction of brain volume, but with a proportionally greater reduction in the volume of the left-sided
prefrontal cortexThe prefrontal cortex is the anterior part of the frontal lobes of the brain, lying in front of the motor and premotor areas.This brain region has been implicated in planning complex cognitive behaviors, personality expression, decision making and moderating correct social behavior...
. These findings suggest that the core ADHD features of inattention, hyperactivity, and impulsivity may reflect
frontal lobe dysfunctionFrontal lobe disorder is an impairment of the frontal lobe that occurs as a result of a number of diseases as well as head trauma. The frontal lobe of the brain plays a key role in higher mental functions such as motivation, planning, social behaviour, and speech production...
, but other brain regions particularly the
cerebellumThe cerebellum is a region of the brain that plays an important role in motor control. It may also be involved in some cognitive functions such as attention and language, and in regulating fear and pleasure responses, but its movement-related functions are the most solidly established...
have also been implicated. Neuroimaging studies in ADHD have not always given consistent results and as of 2008 are only used for research and not diagnostic purposes. A 2005 review of published studies involving neuroimaging, neuropsychological genetics, and neurochemistry found converging lines of evidence to suggest that four connected frontostriatal regions play a role in the pathophysiology of ADHD: The lateral prefrontal cortex,
dorsalIn anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...
anterior cingulate cortexThe anterior cingulate cortex is the frontal part of the cingulate cortex, that resembles a "collar" form around the corpus callosum, the fibrous bundle that relays neural signals between the right and left cerebral hemispheres of the brain...
,
caudateThe caudate nucleus is a nucleus located within the basal ganglia of the brains of many animal species. The caudate nucleus is an important part of the brain's learning and memory system.-Anatomy:...
, and
putamenThe putamen is a round structure located at the base of the forebrain . The putamen and caudate nucleus together form the dorsal striatum. It is also one of the structures that comprises the basal ganglia. Through various pathways, the putamen is connected to the substantia nigra and globus pallidus...
.
In one study a delay in development of certain brain structures by an average of three years occurred in ADHD elementary school aged patients. The delay was most prominent in the frontal cortex and
temporal lobeThe temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....
, which are believed to be responsible for the ability to control and focus thinking. In contrast, the
motor cortexMotor cortex is a term that describes regions of the cerebral cortex involved in the planning, control, and execution of voluntary motor functions.-Anatomy of the motor cortex :The motor cortex can be divided into four main parts:...
in the ADHD patients was seen to mature faster than normal, suggesting that both slower development of behavioral control and advanced motor development might be required for the fidgetiness that characterizes ADHD. It should be noted that stimulant medication itself may affect growth factors of the central nervous system.
The same laboratory had previously found involvement of the "7-repeat" variant of the
dopamine D4 receptorThe dopamine receptor D4 is a G protein-coupled receptor encoded by the gene.As with other dopamine receptor subtypes, the D4 receptor is activated by the neurotransmitter dopamine...
gene, which accounts for about 30 percent of the genetic risk for ADHD, in unusual thinness of the cortex of the right side of the brain; however, in contrast to other variants of the gene found in ADHD patients, the region normalized in thickness during the teen years in these children, coinciding with clinical improvement.
Additionally, SPECT scans found people with ADHD to have reduced blood circulation (indicating low neural activity), and a significantly higher concentration of dopamine transporters in the
striatumThe striatum, also known as the neostriatum or striate nucleus, is a subcortical part of the forebrain. It is the major input station of the basal ganglia system. The striatum, in turn, gets input from the cerebral cortex...
which is in charge of planning ahead. A study by the U.S. Department of Energy’s
Brookhaven National LaboratoryBrookhaven National Laboratory , is a United States national laboratory located in Upton, New York on Long Island, and was formally established in 1947 at the site of Camp Upton, a former U.S. Army base...
in collaboration with
Mount Sinai School of MedicineMount Sinai School of Medicine is an American medical school in the borough of Manhattan in New York City, currently ranked among the top 20 medical schools in the United States. It was chartered by Mount Sinai Hospital in 1963....
in New York suggest that it is not the dopamine transporter levels that indicate ADHD, but the brain's ability to produce
neurotransmitterNeurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...
s like dopamine itself. The study was done by injecting 20 ADHD subjects and 25 control subjects with a radiotracer that attaches itself to dopamine transporters. The study found that it was not the transporter levels that indicated ADHD, but the dopamine itself. ADHD subjects showed lower levels of dopamine (hypodopaminergia) across the board. They speculated that since ADHD subjects had lower levels of dopamine to begin with, the number of transporters in the brain was not the telling factor. In support of this notion, plasma
homovanillic acidHomovanillic acid is a major catecholamine metabolite...
, an index of dopamine levels, was found to be inversely related not only to childhood ADHD symptoms in adult psychiatric patients, but to "childhood learning problems" in healthy subjects as well. One interpretation of dopamine pathway tracers is that the biochemical "reward" mechanism works for those with ADHD only when the task performed is inherently motivating; low levels of dopamine raise the threshold at which someone can maintain focus on a task which is otherwise boring. Neuroimaging studies also found that
neurotransmitterNeurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...
s level (e.g. dopamine and serotonin) in the synaptic cleft goes down during depression.
A 1990
PET scanPositron emission tomography is nuclear medicine imaging technique that produces a three-dimensional image or picture of functional processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide , which is introduced into the body on a...
study by Alan J. Zametkin
et al. found that global cerebral glucose metabolism was 8 percent lower in medication-naive adults who had been hyperactive since childhood. Further studies found that chronic stimulant treatment had little effect on global glucose metabolism, a 1993 study in girls failed to find a decreased global glucose metabolism, but found significant differences in glucose metabolism in 6 specific regions of the brains of ADHD girls as compared to control subjects. The study also found that differences in one specific region of the frontal lobe were statistically correlated with symptom severity. A further study in 1997 also failed to find global differences in glucose metabolism, but similarly found differences in glucose normalization in specific regions of the brain. The 1997 study also noted that their findings were somewhat different than those in the 1993 study, and concluded that sexual maturation may have played a role in this discrepancy. The significance of the research by Zametkin has not been determined and neither his group nor any other has been able to replicate the 1990 results.
Critics, such as Jonathan Leo and David Cohen, who reject the characterization of ADHD as a disorder, contend that the controls for stimulant medication usage were inadequate in some lobar volumetric studies which makes it impossible to determine whether ADHD itself or psychotropic medication used to treat ADHD is responsible for the decreased thickness observed in certain brain regions. While the main study in question used age-matched controls, it did not provide information on height and weight of the subjects. These variables it has been argued could account for the regional brain size differences rather than ADHD itself. They believe many neuroimaging studies are oversimplified in both popular and scientific discourse and given undue weight despite deficiencies in experimental methodology.
Diagnosis
ADHD is diagnosed via a psychiatric assessment; to rule out other potential causes or comorbidities, physical examination, radiological imaging, and laboratory tests may be used.
In North America, the DSM-IV criteria are often the basis for a diagnosis, while European countries usually use the
ICD-10The International Statistical Classification of Diseases and Related Health Problems, 10th Revision is a medical classification list for the coding of diseases, signs and symptoms, abnormal findings, complaints, social circumstances, and external causes of injury or diseases, as maintained by the...
. If the DSM-IV criteria are used, rather than the ICD-10, a diagnosis of ADHD is 3–4 times more likely. Factors other than those within the DSM or ICD however have been found to affect the diagnosis in clinical practice. A child's social and school environment as well as academic pressures at school are likely to be of influence.
Many of the symptoms of ADHD occur from time to time in everyone; in patients with ADHD, the frequency of these symptoms is greater and patients' lives are significantly impaired. Impairment must occur in multiple settings to be classified as ADHD. As with many other psychiatric and medical disorders, the formal diagnosis is made by a qualified professional in the field based on a set number of criteria. In the USA these criteria are laid down by the American Psychiatric Association in their Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), 4th edition. Based on the DSM-IV criteria listed below, three types of ADHD are classified:
- ADHD, Combined Type: if both criteria 1A and 1B are met for the past 6 months
- ADHD Predominantly Inattentive
ADHD predominantly inattentive is one of the three subtypes of Attention-deficit hyperactivity disorder . While ADHD-PI is sometimes still called "attention deficit disorder" by the general public, these older terms were formally changed in 1994 in the new Diagnostic and Statistical Manual of...
Type: if criterion 1A is met but criterion 1B is not met for the past six months
- ADHD, Predominantly Hyperactive-Impulsive Type: if criterion 1B is met but criterion 1A is not met for the past six months.
The previously used term
ADD expired with the most recent revision of the DSM. Consequently, ADHD is the current nomenclature used to describe the disorder as one distinct disorder which can manifest itself as being a primary deficit resulting in hyperactivity/impulsivity (ADHD, predominately hyperactive-impulsive type) or inattention (ADHD predominately inattentive type) or both (ADHD combined type).
DSM-IV
IA. Six or more of the following signs of inattention have been present for at least 6 months to a point that is disruptive and inappropriate for developmental level:
-
- Often does not give close attention to details or makes careless mistakes in schoolwork, work, or other activities.
- Often has trouble keeping attention on tasks or play activities.
- Often does not seem to listen when spoken to directly.
- Often does not follow instructions and fails to finish schoolwork, chores, or duties in the workplace (not due to oppositional behavior or failure to understand instructions).
- Often has trouble organizing activities.
- Often avoids, dislikes, or doesn't want to do things that take a lot of mental effort for a long period of time (such as schoolwork or homework).
- Often loses things needed for tasks and activities (such as toys, school assignments, pencils, books, or tools).
- Is often easily distracted.
- Often forgetful in daily activities.
IB. Six or more of the following signs of hyperactivity-impulsivity have been present for at least 6 months to an extent that is disruptive and inappropriate for developmental level:
-
- Often fidgets with hands or feet or squirms in seat.
- Often gets up from seat when remaining in seat is expected.
- Often runs about or climbs when and where it is not appropriate (adolescents or adults may feel very restless).
- Often has trouble playing or enjoying leisure activities quietly.
- Is often "on the go" or often acts as if "driven by a motor".
- Often talks excessively.
-
- Often blurts out answers before questions have been finished.
- Often has trouble waiting one's turn.
- Often interrupts or intrudes on others (example: butts into conversations or games).
II. Some signs that cause impairment were present before age 7 years.
III. Some impairment from the signs is present in two or more settings (such as at school/work and at home).
IV. There must be clear evidence of significant impairment in social, school, or work functioning.
V. The signs do not happen only during the course of a Pervasive Developmental Disorder,
SchizophreniaSchizophrenia is a mental disorder characterized by a disintegration of thought processes and of emotional responsiveness. It most commonly manifests itself as auditory hallucinations, paranoid or bizarre delusions, or disorganized speech and thinking, and it is accompanied by significant social...
, or other Psychotic Disorder. The signs are not better accounted for by another mental disorder (such as
Mood DisorderMood disorder is the term designating a group of diagnoses in the Diagnostic and Statistical Manual of Mental Disorders classification system where a disturbance in the person's mood is hypothesized to be the main underlying feature...
,
Anxiety DisorderAnxiety disorder is a blanket term covering several different forms of abnormal and pathological fear and anxiety. Conditions now considered anxiety disorders only came under the aegis of psychiatry at the end of the 19th century. Gelder, Mayou & Geddes explains that anxiety disorders are...
,
Dissociative Identity DisorderDissociative identity disorder is a psychiatric diagnosis and describes a condition in which a person displays multiple distinct identities , each with its own pattern of perceiving and interacting with the environment....
, or a
Personality DisorderPersonality disorders, formerly referred to as character disorders, are a class of personality types and behaviors. Personality disorders are noted on Axis II of the Diagnostic and Statistical Manual of Mental Disorders or DSM-IV-TR of the American Psychiatric Association.Personality disorders are...
).
ICD-10
In the tenth edition of the
International Statistical Classification of Diseases and Related Health Problems (ICD-10) the signs of ADHD are given the name "
Hyperkinetic disordersHyperkinesia, also known as hyperkinesis, refers to an increase in muscular activity that can result in excessive abnormal movements, excessive normal movements, or a combination of both...
". When a
conduct disorderConduct disorder is psychological disorder diagnosed in childhood that presents itself through a repetitive and persistent pattern of behavior in which the basic rights of others or major age-appropriate norms are violated...
(as defined by ICD-10) is present, the condition is referred to as "Hyperkinetic conduct disorder". Otherwise the disorder is classified as "Disturbance of Activity and Attention", "Other Hyperkinetic Disorders" or "Hyperkinetic Disorders, Unspecified". The latter is sometimes referred to as, "Hyperkinetic Syndrome".
Other guidelines
The
American Academy of PediatricsThe American Academy of Pediatrics is the major professional association of pediatricians in the United States. The AAP was founded in 1930 by 35 pediatricians to address pediatric healthcare standards. It currently has 60,000 members in primary care and sub-specialist areas...
Clinical Practice GuidelineA medical guideline is a document with the aim of guiding decisions and criteria regarding diagnosis, management, and treatment in specific areas of healthcare...
for children with ADHD emphasizes that a reliable diagnosis is dependent upon the fulfillment of three criteria:
- The use of explicit criteria for the diagnosis using the DSM-IV-TR.
- The importance of obtaining information about the child’s signs in more than one setting.
- The search for coexisting conditions that may make the diagnosis more difficult or complicate treatment planning.
All three criteria are determined using the patient's history given by the parents, teachers and/or the patient.
Adults often continue to be impaired by ADHD. Adults with ADHD are diagnosed under the same criteria, including the stipulation that their signs must have been present prior to the age of seven. Adults face some of their greatest challenges in the areas of self-control and self-motivation, as well as executive functioning, usually having more signs of inattention and fewer of hyperactivity or impulsiveness than children do.
The American Academy of Child Adolescent Psychiatry (AACAP) considers it necessary that the following be present before attaching the label of ADHD to a child:
- The behaviors must appear before age 7.
- They must continue for at least six months.
- The symptoms must also create a real handicap in at least two of the following areas of the child’s life:
- in the classroom,
- on the playground,
- at home,
- in the community, or
- in social settings.
If a child seems too active on the playground but not elsewhere, the problem might not be ADHD. It might also not be ADHD if the behaviors occur in the classroom but nowhere else. A child who shows some symptoms would not be diagnosed with ADHD if his or her schoolwork or friendships are not impaired by the behaviors.
Differential
To make the diagnosis of ADHD, a number of other possible medical and psychological conditions must be excluded.
Medical conditions
Medical conditions that must be excluded include:
hypothyroidismHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
,
anemiaAnemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
,
lead poisoningLead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems...
, chronic illness,
hearingHearing is the ability to perceive sound by detecting vibrations through an organ such as the ear. It is one of the traditional five senses...
or
visionVisual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...
impairment,
substance abuseA substance-related disorder is an umbrella term used to describe several different conditions associated with several different substances .A substance related disorder is a condition in which an individual uses or abuses a...
,
medication side effectsIn medicine, an adverse effect is a harmful and undesired effect resulting from a medication or other intervention such as surgery.An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. If it results from an unsuitable or incorrect dosage or...
, sleep impairment and
child abuseChild abuse is the physical, sexual, emotional mistreatment, or neglect of a child. In the United States, the Centers for Disease Control and Prevention and the Department of Children And Families define child maltreatment as any act or series of acts of commission or omission by a parent or...
, and
clutteringCluttering is a speech disorder and a communication disorder characterized by speech that is difficult for listeners to understand due to rapid speaking rate, erratic rhythm, poor syntax or grammar, and words or groups of words unrelated to the sentence...
(tachyphemia) among others.
Sleep conditions
As with other psychological and neurological issues, the relationship between ADHD and
sleepSleep is a naturally recurring state characterized by reduced or absent consciousness, relatively suspended sensory activity, and inactivity of nearly all voluntary muscles. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and is more easily reversible than...
is complex. In addition to clinical observations, there is substantial empirical evidence from a neuroanatomic standpoint to suggest that there is considerable overlap in the central nervous system centers that regulate sleep and those that regulate attention/arousal. Primary sleep disorders play a role in the clinical presentation of symptoms of inattention and behavioral dysregulation. There are multilevel and bidirectional relationships among sleep, neurobehavioral functioning and the clinical syndrome of ADHD.
Behavioral manifestations of sleepiness in children range from the classic ones (yawning, rubbing eyes), to externalizing behaviors (impulsivity, hyperactivity, aggressiveness), to mood lability and inattentiveness. Many sleep disorders are important causes of symptoms which may overlap with the cardinal symptoms of ADHD; children with ADHD should be regularly and systematically assessed for sleep problems.
From a clinical standpoint, mechanisms that account for the phenomenon of excessive daytime sleepiness include:
- Chronic sleep deprivation
Sleep deprivation is the condition of not having enough sleep; it can be either chronic or acute. A chronic sleep-restricted state can cause fatigue, daytime sleepiness, clumsiness and weight loss or weight gain. It adversely affects the brain and cognitive function. Few studies have compared the...
, that is insufficient sleep for physiologic sleep needs,
- Fragmented or disrupted sleep, caused by, for example, obstructive sleep apnea
Obstructive sleep apnea or obstructive sleep apnea syndrome is the most common type of sleep apnea and is caused by obstruction of the upper airway. It is characterized by repetitive pauses in breathing during sleep, despite the effort to breathe, and is usually associated with a reduction in...
(OSA) or periodic limb movement disorder (PLMD),
- Primary clinical disorders of excessive daytime sleepiness, such as narcolepsy
Narcolepsy is a chronic sleep disorder, or dyssomnia, characterized by excessive sleepiness and sleep attacks at inappropriate times, such as while at work. People with narcolepsy often experience disturbed nocturnal sleep and an abnormal daytime sleep pattern, which often is confused with insomnia...
and
- Circadian rhythm disorders, such as delayed sleep phase syndrome
Delayed sleep-phase syndrome , also known as delayed sleep-phase disorder or delayed sleep-phase type , is a circadian rhythm sleep disorder, a chronic disorder of the timing of sleep, peak period of alertness, the core body temperature rhythm, hormonal and other daily rhythms, compared to the...
(DSPS). A study in the Netherlands compared two groups of unmedicated 6-12-year-olds, all of them with "rigorously diagnosed ADHD". 87 of them had problems getting to sleep, 33 had no sleep problems. The larger group had a significantly later dim light melatonin onset (DLMO) than did the children with no sleep problems.
Management
Methods of treatment often involve some combination of behavior modification, life-style changes, counseling, and medication. A 2005 study found that medical management and behavioral treatment is the most effective ADHD management strategy, followed by medication alone, and then behavioral treatment. While medication has been shown to improve behavior when taken over the short term, they have not been shown to alter long term outcomes. Medications have at least some effect in about 80% of people.
Psychosocial
The evidence is strong for the effectiveness of behavioral treatments in ADHD. It is recommended first line in those who have mild symptoms and in preschool aged children. Psychological therapies used include
psychoeducationalPsychoeducational assessment and intervention target a student's function within his or her educational setting....
input, behavior therapy, cognitive behavioral therapy (CBT),
interpersonal psychotherapyInterpersonal Psychotherapy is a time-limited psychotherapy that focuses on the interpersonal context and on building interpersonal skills. IPT is based on the belief that interpersonal factors may contribute heavily to psychological problems. It is commonly distinguished from other forms of...
(IPT),
family therapyFamily therapy, also referred to as couple and family therapy, family systems therapy, and family counseling, is a branch of psychotherapy that works with families and couples in intimate relationships to nurture change and development. It tends to view change in terms of the systems of...
, school-based interventions, social skills training and parent management training. Parent training and education have been found to have short term benefits. There is a deficiency of good research on the effectiveness of family therapy for ADHD, but the evidence that exists shows that it is comparable in effectiveness to treatment as usual in the community and is superior to medication placebo. It may be worth noting that parents of children with ADHD are more likely to divorce than parents of children without ADHD, particularly when their children are younger than eight years old. Several
ADHD specific support groups exist as informational sources and to help families cope with challenges associated with dealing with ADHD.
Medication
StimulantStimulants are psychoactive drugs which induce temporary improvements in either mental or physical function or both. Examples of these kinds of effects may include enhanced alertness, wakefulness, and locomotion, among others...
medication are the medical treatment of choice. There are a number of non-stimulant medications, such as
atomoxetine, that may be used as alternatives. There are no good studies of comparative effectiveness between various medications, and there is a lack of evidence on their effects on academic performance and social behaviors. While stimulants and atomoxetine are generally safe, there are side effects and contraindications to their use. Medications are not recommended for preschool children, as their long-term effects in such young people are unknown. There is very little data on the long-term benefits or adverse effects of stimulants for ADHD. Any drug used for ADHD may have adverse drug reactions such as
psychosisPsychosis means abnormal condition of the mind, and is a generic psychiatric term for a mental state often described as involving a "loss of contact with reality"...
and
maniaMania, the presence of which is a criterion for certain psychiatric diagnoses, is a state of abnormally elevated or irritable mood, arousal, and/ or energy levels. In a sense, it is the opposite of depression...
, though
methylphenidateMethylphenidate is a psychostimulant drug approved for treatment of attention-deficit hyperactivity disorder, postural orthostatic tachycardia syndrome and narcolepsy. It may also be prescribed for off-label use in treatment-resistant cases of lethargy, depression, neural insult and obesity...
-induced psychosis is uncommon. People with ADHD have an increased risk of
substance abuseA substance-related disorder is an umbrella term used to describe several different conditions associated with several different substances .A substance related disorder is a condition in which an individual uses or abuses a...
, and stimulant medications reduce this risk. Stimulants medications in and of themselves however have the potential for abuse and dependence. Guidelines on when to use medications vary internationally, with the UK's National Institute of Clinical Excellence, for example, only recommending use in severe cases, while most United States guidelines recommend medications in nearly all cases.
Prognosis
Children diagnosed with ADHD have significant difficulties in adolescence, regardless of treatment. In the United States, 37 percent of those with ADHD do not get a high school diploma even though many of them will receive special education services. A 1995 briefing citing a 1994 book review says the combined outcomes of the expulsion and dropout rates indicate that almost half of all ADHD students never finish high school. Also in the US, less than 5 percent of individuals with ADHD get a college degree compared to 28 percent of the general population. Those with ADHD as children are at increased risk of a number of adverse life outcomes once they become teenagers. These include a greater risk of auto crashes, injury and higher medical expenses, earlier sexual activity, and teen pregnancy. Russell Barkley states that adult ADHD impairments affect "education, occupation, social relationships, sexual activities, dating and marriage, parenting and offspring psychological morbidity, crime and drug abuse, health and related lifestyles, financial management, or driving. ADHD can be found to produce diverse and serious impairments".
The proportion of children meeting the diagnostic criteria for ADHD drops by about 50 percent over three years after the diagnosis. This occurs regardless of the treatments used and also occurs in untreated children with ADHD. ADHD persists into adulthood in about 30 to 50 percent of cases. Those affected are likely to develop coping mechanisms as they mature, thus compensating for their previous ADHD.
Epidemiology
ADHD's global
prevalenceIn epidemiology, the prevalence of a health-related state in a statistical population is defined as the total number of cases of the risk factor in the population at a given time, or the total number of cases in the population, divided by the number of individuals in the population...
is estimated at 3 to 5 percent in people under the age of 19. There is, however, both geographical and local variability among studies. Geographically, children in North America appear to have a higher rate of ADHD than children in Africa and the Middle East. Published studies have found rates of ADHD as low as 2 percent and as high as 14 percent among school aged children. The rates of diagnosis and treatment of ADHD are also much higher on the East Coast of the USA than on the West Coast. The frequency of the diagnosis differs between male children (10%) and female children (4%) in the United States. This difference between genders may reflect either a difference in susceptibility or that females with ADHD are less likely to be diagnosed than males.
Rates of ADHD diagnosis and treatment have increased in both the UK and the USA since the 1970s. In the UK an estimated 0.5 per 1,000 children had ADHD in the 1970s, while 3 per 1,000 received ADHD medications in the late 1990s. In the USA in the 1970s 12 per 1,000 children had the diagnosis, while in the late 1990s 34 per 1,000 had the diagnosis and the numbers continue to increase.
In the UK in 2003 a prevalence of 3.6 percent is reported in male children and less than 1 percent is reported in female children.
History
Hyperactivity has long been part of the human condition. Sir
Alexander CrichtonSir Alexander Crichton was a Scottish doctor, physician and author.- Medical career :Born in Newington, Edinburgh, Crichton received his M.D. from Leyden, Holland, in 1785. He developed his medical skills through studies at Paris, Stuttgart, Vienna, and Halle...
describes "mental restlessness" in his book
An Inquiry Into the Nature and Origin of Mental Derangement written in 1798. The terminology used to describe the symptoms of ADHD has gone through many changes over history including: "minimal brain damage", "minimal brain dysfunction" (or disorder), "learning/behavioral disabilities" and "hyperactivity". In the DSM-II (1968) it was the "Hyperkinetic Reaction of Childhood". In the DSM-III "ADD (Attention-Deficit Disorder) with or without hyperactivity" was introduced. In 1987 this was changed to ADHD in the DSM-III-R and subsequent editions. The use of stimulants to treat ADHD was first described in 1937.
Society and culture
The media have reported on many issues related to ADHD. In 2001
PBSThe Public Broadcasting Service is an American non-profit public broadcasting television network with 354 member TV stations in the United States which hold collective ownership. Its headquarters is in Arlington, Virginia....
's Frontline aired a one-hour program about the effects of the diagnosis and treatment of ADHD in minors, entitled "Medicating Kids." The program included a selection of interviews with representatives of various points of view. In one segment, entitled Backlash, retired
neurologistA neurologist is a physician who specializes in neurology, and is trained to investigate, or diagnose and treat neurological disorders.Neurology is the medical specialty related to the human nervous system. The nervous system encompasses the brain, spinal cord, and peripheral nerves. A specialist...
Fred BaughmanFred Baughman is best known as an outspoken critic of psychiatry, who claims that attention-deficit hyperactivity disorder is "a fraud perpetrated by the psychiatric and pharmaceutical industries on families anxious to understand their childrens' behavior". Baughman has testified before the...
and
Peter BregginPeter Roger Breggin is an American psychiatrist and critic of biological psychiatry and psychiatric medication. In his books, he advocates replacing psychiatry's use of drugs and electroconvulsive therapy with humanistic approaches, such as psychotherapy, education, and broader human...
whom PBS described as "outspoken critics who insist [ADHD is] a fraud perpetrated by the psychiatric and pharmaceutical industries on families anxious to understand their children's behavior" were interviewed on the legitimacy of the disorder.
Russell BarkleyRussell A. Barkley, Ph.D., is a Research Professor in the Department of Psychiatry at the State University of New York Upstate Medical University...
and Xavier Castellanos, then head of ADHD research at the
National Institute of Mental HealthThe National Institute of Mental Health is one of 27 institutes and centers that make up the National Institutes of Health...
(NIMH), defended the viability of the disorder. In the interview with Castellanos, he stated that little is scientifically understood. Lawrence Diller was interviewed on the business of ADHD along with a representative from Shire Plc (then known as Shire-Richwood).
A number of notable individuals have given controversial opinions on ADHD.
ScientologistScientology is a body of beliefs and related practices created by science fiction and fantasy author L. Ron Hubbard , starting in 1952, as a successor to his earlier self-help system, Dianetics...
Tom CruiseThomas Cruise Mapother IV , better known as Tom Cruise, is an American film actor and producer. He has been nominated for three Academy Awards and he has won three Golden Globe Awards....
's interview with
Matt LauerMatthew Todd "Matt" Lauer . is an American television journalist best known as the host of NBC's The Today Show since 1997. He was previously a news anchor in New York and a local talk-show host in Boston, Philadelphia, Providence and Richmond...
was widely watched by the public. In this interview he spoke about
postpartum depressionPostpartum depression , also called postnatal depression, is a form of clinical depression which can affect women, and less frequently men, typically after childbirth. Studies report prevalence rates among women from 5% to 25%, but methodological differences among the studies make the actual...
and also referred to Ritalin and
AdderallAdderall is a brand name of amphetamine salts–based medication used for attention-deficit hyperactivity disorder and narcolepsy. It is a brand-name psychostimulant medication composed of racemic amphetamine aspartate monohydrate, racemic amphetamine sulfate, dextroamphetamine saccharide, and...
as being "street drugs" rather than as ADHD medication. In England
BaronessThe House of Lords is the upper house of the Parliament of the United Kingdom. Like the House of Commons, it meets in the Palace of Westminster....
Susan GreenfieldSusan Adele Greenfield, Baroness Greenfield, CBE is a British scientist, writer, broadcaster, and member of the House of Lords. Greenfield, whose specialty is the physiology of the brain, has worked to research and bring attention to Parkinson's disease and Alzheimer's disease.Greenfield is...
, a leading neuroscientist, spoke out publicly about the need for a wide-ranging inquiry in the House of Lords into the dramatic increase in the diagnosis of ADHD in the UK and possible causes following a 2007 BBC Panorama programme which highlighted US research (The Multimodal Treatment Study of Children with ADHD by the University of Buffalo showing treatment results of 600) suggesting drugs are no better than other forms of therapy for ADHD in the long term.
Neil BushNeil Mallon Bush is the fourth of six children of former President George Herbert Walker Bush and Barbara Bush . His five siblings are George Walker Bush, the former President of the United States; Jeb Bush, the former governor of Florida; Robin Bush, who died of leukemia in 1953 at the age of...
(brother of former President
George W. BushGeorge Walker Bush is an American politician who served as the 43rd President of the United States, from 2001 to 2009. Before that, he was the 46th Governor of Texas, having served from 1995 to 2000....
) is credited in the cast of a 2005 ADHD documentary called
The Drugging of Our Children directed by
Gary NullGary Michael Null is an American talk radio host and author on alternative and complementary medicine and nutrition. On his talk radio show and in his books and self-produced movies, Null has criticized the medical community, promoted a range of alternative cancer treatments and dietary...
. In the film's trailer Bush says: "Just because it is easy to drug a kid and get them to be compliant doesn't make it right to do it".
, eight percent of all
Major League BaseballMajor League Baseball is the highest level of professional baseball in the United States and Canada, consisting of teams that play in the National League and the American League...
players have been diagnosed with ADHD, making the disorder
epidemicIn epidemiology, an epidemic , occurs when new cases of a certain disease, in a given human population, and during a given period, substantially exceed what is expected based on recent experience...
among this population. The increase coincided with the League's 2006 ban on
stimulantStimulants are psychoactive drugs which induce temporary improvements in either mental or physical function or both. Examples of these kinds of effects may include enhanced alertness, wakefulness, and locomotion, among others...
s (q.v.
Major League Baseball drug policyMajor League Baseball's drug policy—the Joint Drug Prevention and Treatment Program—was established by agreement between the MLB Players Association and the Office of the Commissioner of Baseball in order to deter and end the use by baseball players of banned substances, including anabolic steroids...
).
Legal status of medications
Stimulants legal status was recently reviewed by several international organizations:
- Internationally, methylphenidate is a Schedule II drug under the Convention on Psychotropic Substances
The Convention on Psychotropic Substances of 1971 is a United Nations treaty designed to control psychoactive drugs such as amphetamines, barbiturates, benzodiazepines, and psychedelics signed at Vienna on February 21, 1971...
.
- In the United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, methylphenidate is classified as a Schedule IIThe Controlled Substances Act was enacted into law by the Congress of the United States as Title II of the Comprehensive Drug Abuse Prevention and Control Act of 1970. The CSA is the federal U.S. drug policy under which the manufacture, importation, possession, use and distribution of certain...
controlled substanceA controlled substance is generally a drug or chemical whose manufacture, possession, or use are regulated by a government. This may include illegal drugs and prescription medications ....
, the designation used for substances that have a recognized medical value but present a high likelihood for abuse because of their addictive potential.
- In the United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, methylphenidate is a controlled 'Class B' substance, and possession without prescription is illegal, with a sentence up to 14 years and/or an unlimited fine.
- In New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
, it is a 'class B2 controlled substance'. unlawful possession is punishable by 6-month prison sentence and distribution of it is punishable by a 14-year sentence.
Controversies
ADHD and its diagnosis and treatment have been considered controversial since the 1970s. The controversies have involved clinicians, teachers, policymakers, parents and the media. Opinions regarding ADHD range from not believing it exists at all to believing there are genetic and physiological bases for the condition as well as disagreement about the use of stimulant medications in treatment. Some sociologists consider ADHD to be a "classic example of the medicalization of deviant behavior, defining a previously nonmedical problem as a medical one". Most healthcare providers in U.S. accept that ADHD is a genuine disorder with debate in centering mainly around how it is diagnosed and treated. However, The
British Psychological SocietyThe British Psychological Society is a representative body for psychologists and psychology in the United Kingdom. The BPS is also a Registered Charity and, along with advantages, this also imposes certain constraints on what the society can and cannot do...
said in a 1997 report that physicians and psychiatrists should not follow the American example of applying medical labels to such a wide variety of attention-related disorders: "The idea that children who don’t attend or who don’t sit still in school have a mental disorder is not entertained by most British clinicians." In 2009, the British Psychological Society, in collaboration with the Royal College of Psychiatrists, released a set of guidelines for the diagnosis and treatment of ADHD. In its guideline, it state that available evidence indicate that ADHD is a valid diagnosis. However, it states that the diagnosis lack any biological basis and that "[c]ontroversial issues surround changing thresholds applied to the definition of illness as new knowledge and treatments are developed and the extent to which it is acknowledged that clinical thresholds are socially and culturally influenced and determine how an individual's level of functioning within the 'normal cultural environment' is assessed". It further states that "the acceptable thresholds for impairment are partly driven by the contemporary societal view of what is an acceptable level of deviation from the norm."
Others have included that it may stem from a misunderstanding of the diagnostic criteria and how they are utilized by clinicians, teachers, policymakers, parents and the media. Debates center around key controversial issues; whether ADHD is a disability or merely a neurological description, the cause of the disorder, the changing of the diagnostic criteria, the rapid increase in diagnosis of ADHD, and the use of stimulants to treat the disorder. Long term possible side effects of stimulants and their usefulness are largely unknown because of a lack of long term studies. Some research raises questions about the long term effectiveness and side effects of medications used to treat ADHD.
In 1998, the US National Institutes of Health (NIH) released a consensus statement on the diagnosis and treatment of ADHD. The statement, while recognizing that stimulant treatment is controversial, supports the validity of the ADHD diagnosis and the efficacy of stimulant treatment. It found controversy only in the lack of sufficient data on long-term use of medications, and in the need for more research in many areas.
With a "wide variation in diagnosis across states, races, and ethnicities" some investigators suspect that factors other than neurological conditions play a role when the diagnosis of ADHD is made. Two studies published in 2010 suggest that the diagnosis is more likely to be made in the younger children within a grade; the authors propose that such a misdiagnosis of ADHD within a grade may be due to different states of maturity and may lead to potentially inappropriate treatment.
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