Acute stress reaction
Encyclopedia
Acute stress reaction is a psychological
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...

 condition arising in response to a terrifying or traumatic event. It should not be confused with the unrelated circulatory condition of shock.

"Acute stress response" was first described by Walter Cannon in the 1920s as a theory that animals react to threats with a general discharge of the sympathetic nervous system
Sympathetic nervous system
The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...

. The response was later recognized as the first stage of a general adaptation syndrome that regulates stress responses among vertebrates and other organisms.

The onset of a stress response is associated with specific physiological actions in the sympathetic nervous system, both directly and indirectly through the release of adrenaline and to a lesser extent noradrenaline from the medulla
Adrenal medulla
The adrenal medulla is part of the adrenal gland. It is located at the center of the gland, being surrounded by the adrenal cortex. It is the innermost part of the adrenal gland, consisting of cells that secrete epinephrine , norepinephrine , and a small amount of dopamine in response to...

 of the adrenal gland
Adrenal gland
In mammals, the adrenal glands are endocrine glands that sit atop the kidneys; in humans, the right suprarenal gland is triangular shaped, while the left suprarenal gland is semilunar shaped...

s. These catecholamine hormone
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...

s facilitate immediate physical reactions by triggering increases in heart rate and breathing, constricting blood vessels. An abundance of catecholamines at neuroreceptor sites facilitates reliance on spontaneous or intuitive behaviors often related to combat or escape.

Normally, when a person is in a serene, unstimulated state, the "firing" of neurons in the locus ceruleus
Locus ceruleus
The locus coeruleus , is a nucleus in the brainstem involved with physiological responses to stress and panic. It was discovered in the 18th century by Félix Vicq-d'Azyr....

 is minimal. A novel stimulus, once perceived, is relayed from the sensory cortex
Sensory cortex
The sensory cortex can refer informally to the primary somatosensory cortex, or it can be used as an umbrella term for the primary and secondary cortices of the different senses : the visual cortex on the occipital lobes, the auditory cortex on the temporal lobes, the primary olfactory cortex on...

 of the brain through the thalamus
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...

 to the brain stem
Brain stem
In vertebrate anatomy the brainstem is the posterior part of the brain, adjoining and structurally continuous with the spinal cord. The brain stem provides the main motor and sensory innervation to the face and neck via the cranial nerves...

. That route of signaling increases the rate of noradrenergic activity in the locus ceruleus, and the person becomes alert and attentive to the environment.

If a stimulus is perceived as a threat, a more intense and prolonged discharge of the locus ceruleus activates the sympathetic division of the autonomic nervous system (Thase & Howland, 1995). The activation of the sympathetic nervous system leads to the release of noradrenaline from nerve endings acting on the heart, blood vessels, respiratory centers, and other sites. The ensuing physiological changes constitute a major part of the acute stress response. The other major player in the acute stress response is the hypothalamic-pituitary-adrenal axis
Hypothalamic-pituitary-adrenal axis
The hypothalamic-pituitary-adrenal axis , also known as thelimbic-hypothalamic-pituitary-adrenal axis and, occasionally, as the hypothalamic-pituitary-adrenal-gonadotropic axis, is a complex set of direct influences and feedback interactions among the hypothalamus, the pituitary gland ,...

.

Causes

By definition, acute stress disorder is the result of a traumatic event
Traumatic event
A traumatic event is an event that is or may be a cause of trauma. The term may refer to one of the followiong:*Traumatic event , an event associated with a physical trauma...

 in which the person experiences or witnesses an event that causes the victim/witness to experience extreme, disturbing or unexpected fear, stress or pain, and that involves or threatens serious injury, perceived serious injury or death to themselves or someone else. Acute stress reaction is a variation of Post-Traumatic Stress Disorder
Post-traumatic stress disorder
Posttraumaticstress disorder is a severe anxiety disorder that can develop after exposure to any event that results in psychological trauma. This event may involve the threat of death to oneself or to someone else, or to one's own or someone else's physical, sexual, or psychological integrity,...

 (PTSD) and is the mind's and body's response to feelings (both perceived and real) of intense helplessness.

Symptoms of acute stress reaction

The symptoms show great variation but typically include an initial state of "daze", with some constriction of the field of consciousness and narrowing of attention, inability to comprehend stimuli, and disorientation.

This state may be quickly followed by either further withdrawal from the surrounding situation (to the extent of a dissociative stupor), or by agitation and overactivity, anxiety, impaired judgement, confusion, detachment, and depression. Autonomic signs of panic anxiety (tachycardia, sweating, flushing) are also commonly present.

The symptoms usually appear within minutes of the impact of the stressful stimulus or event, and disappear within 2–3 days (often within hours). Partial or complete amnesia for the episode may be present.

Symptoms of acute stress disorder

Common symptoms that sufferers of acute stress disorder experience are: numbing; detachment; derealization; depersonalization or dissociative amnesia; continued re-experiencing of the event by such ways as thoughts, dreams, and flashbacks; and avoidance of any stimulation that reminds them of the event. During this time, they must have symptoms of anxiety, and significant impairment in at least one essential area of functioning. Symptoms last for a minimum of 2 days, and a maximum of 4 weeks, and occur within 4 weeks of the event.

Diagnostic guidelines

There must be an immediate and clear temporal connection between the impact of an exceptional stressor and the onset of symptoms; onset is usually within a few minutes, if not immediate. In addition, the symptoms show a mixed and usually changing picture; in addition to the initial state of "daze", depression, anxiety, anger, despair, overactivity, and withdrawal may all be seen, but no one type of symptom predominates for long; resolve rapidly (within a few hours at the most) in those cases where removal from the stressful environment is possible; in cases where the stress continues or cannot by its nature be reversed, the symptoms usually begin to diminish after 24–48 hours and are usually minimal after about 3 days.

If symptoms last for more than a month, then the patient might be instead diagnosed with PTSD.

Treatment

This disorder may resolve itself with time or may develop into a more severe disorder such as PTSD. However, results of Creamer, O'Donnell, and Pattison's (2004) study of 363 patients suggests that a diagnoses of Acute Stress Disorder had only limited predictive validity for PTSD. Creamer et al. did however find that re-experiences of the traumatic event and arousal were better predictors of PTSD. Medication can be used for a very short duration (up to four weeks).

A number of studies have been conducted to assess the efficacy of counselling and psychotherapy for people with ASD. Cognitive behavioral therapy which included exposure and cognitive restructuring was found to be effective in preventing PTSD in patients diagnosed with ASD with clinically significant results at 6 months follow-up. A combination of relaxation, cognitive restructuring, imaginal exposure, and in vivo exposure was superior to supportive counselling.

See also

  • Combat stress reaction
    Combat stress reaction
    Combat stress reaction , in the past commonly known as shell shock or battle fatigue, is a range of behaviours resulting from the stress of battle which decrease the combatant's fighting efficiency. The most common symptoms are fatigue, slower reaction times, indecision, disconnection from one's...

  • Fight-or-flight response
    Fight-or-flight response
    The fight-or-flight response was first described by Walter Bradford Cannon....

  • Posttraumatic stress disorder
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