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Neuropsychiatry
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Neuropsychiatry is the branch of medicine dealing with mental disorders attributable to diseases of the nervous system.
It preceded the current disciplines of psychiatry and neurology, in as much as psychiatrists and neurologists had a common training (Yudofsky and Hales, 2002). However, neurology and psychiatry subsequently split apart and are typically practised separately. Nevertheless, neuropsychiatry has become a growing subspecialty of psychiatry and it is also closely related to the field of Behavioral Neurology, which is a subspecialty of Neurology that addresses clinical problems of cognition and/or behavior caused by brain injury or brain disease.
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Neuropsychiatry is the branch of medicine dealing with mental disorders attributable to diseases of the nervous system.
It preceded the current disciplines of psychiatry and neurology, in as much as psychiatrists and neurologists had a common training (Yudofsky and Hales, 2002). However, neurology and psychiatry subsequently split apart and are typically practised separately. Nevertheless, neuropsychiatry has become a growing subspecialty of psychiatry and it is also closely related to the field of Behavioral Neurology, which is a subspecialty of Neurology that addresses clinical problems of cognition and/or behavior caused by brain injury or brain disease. 'Behavioral Neurology / Neuropsychiatry' fellowships are jointly accredited through the United Council for Neurologic Subspecialties (UCNS), in a manner similar to how the specialties of psychiatry and neurology in the United States have a joint board for accreditation, the American Board of Psychiatry and Neurology (ABPN).
The case for the rapprochement of neurology and psychiatry
Given the considerable overlap between these subspecialities, there has been a resurgence of interest and debate relating to neuropsychiatry in acedemia over the last decade. E.g.:
- Yudofsky S. C., & Hales E.H (2002). Neuropsychiatry and the Future of Psychiatry and Neurology. American Journal of Psychiatry, 159(8), 1261-1264.
- Price, B.H., Adams, R.D., & Coyle, J.T. (2000). Neurology and psychiatry: closing the great divide. Neurology, 54(1), 8-14.
- Martin, J. B. (2002). The Integration of Neurology, Psychiatry, and Neuroscience in the 21st Century. American Journal of Psychiatry, 159(5), 695 – 704.
- Kendler, K. S. (2005). Toward a Philosophical Structure for Psychiatry. American Journal of Psychiatry, 162, 433-440.
Most of this work argues for a rapprochement of neurology and psychiatry, forming a speciality above and beyond a subspecialty of psychiatry. For example, Professor Joseph B. Martin, Dean of Harvard Medical School and a neurologist by training, has summarized the argument for reunion: "the separation of the two categories is arbitrary, often influenced by beliefs rather than proven scientific observations. And the fact that the brain and mind are one makes the separation artificial anyway.'" (Martin, 2002). These points and some of the other major arguments are detailed below.
Mind/brain monism
Neurologists have focused objectively on organic nervous system pathology, especially of the brain, whereas psychiatrists have laid claim to illnesses of the mind. This antipodal distinction between brain and mind as two different entities has characterized many of the differences between the two specialties. However, it is argued that this division is simply not veridical; a plethora of evidence from the last century of research has shown that our mental life has its roots in the brain (see Martin, 2002). Brain and mind are argued not to be discrete entities but just different ways of looking at the same system (Marr, 1982). It has been argued that embracing this mind/brain monism is important for several reasons. Firstly, rejecting dualism logically implies that all mentation is biological and so immediately there is a common research framework in which understanding – and thus treatment – of mental suffering can be advanced. Secondly, it removes the widespread confusion about the legitimacy of mental illness: all disorders should have a footprint in the brain-mind system.
In sum, one reason for the division between psychiatry and neurology was the difference between mind or first-person experience and brain. That this difference is artificial is taken as good support for a merge between these specialties.
Causal pluralism
Another broad reason for the divide is that neurology traditionally looks at the causes of disorders from an ‘inside-the-skin’ perspective (neuropathology, genetics) whereas psychiatry looks at ‘outside-the-skin’ causation (personal, interpersonal, cultural) (Kendler, 2005). This dichotomy is argued not to be instructive and authors have argued that it is better conceptualised as two ends of a causal continuum (e.g. Kendler, 2005). The benefits of this position are: Firstly, understanding of aetiology will be enriched, in particular between brain and environment. One example is eating disorders, which have been found to have some neuropathology (Uher and Treasure, 2005) but also show increased incidence in rural Fijian school girls after exposure to television (Becker, 2004). Another example is schizophrenia, the risk for which may be considerably reduced in a healthy family environment (Tienari et al, 2004).
Secondly, it is argued that this augmented understanding of aetiology will lead to better remediation and rehabilitation strategies through an understanding of the different levels in the causal process where one can intervene. Indeed, it may be that non-organic interventions, like cognitive behavioural therapy (CBT), better attenuate disorders alone or in conjunction with drugs. Linden’s (2006) demonstration of how psychotherapy has neurobiological commonalities with pharmacotherapy is a pertinent example of this and is encouraging from a patient perspective as the potentiality for pernicious side effects is decreased whilst self-efficacy is increased.
In sum, the argument is that an understanding of the mental disorders must not only have a specific knowledge of brain constituents and genetics (inside-the-skin) but also the context (outside-the-skin) in which these parts operate (Koch and Laurent, 1999). Only by joining neurology and psychiatry, it is argued, can this nexus be used to reduce human suffering.
Hitherto psychiatric disorders have organic basis
To further sketch psychiatry’s history shows a departure from structural neuropathology, relying more upon ideology (Sabshin, 1990). A good example of this is Tourette's syndrome, which Ferenczi (1921), although never having seen a patient with Tourette's syndrome, suggested was the symbolic expression of masturbation caused by sexual repression. However, starting with the efficacy of neuroleptic drugs in attenuating symptoms (Shapiro, Shapiro and Wayne, 1973) the syndrome has gained pathophysiological support (e.g. Singer, 1997) and is hypothesized to have a genetic basis too based on its high inheritability (Robertson, 2000). This trend can be seen for many hitherto traditionally psychiatric disorders (Table 1) and is argued to support reuniting neurology and psychiatry because both are dealing with disorders of the same system.
Table 1 | Linking traditionally psychiatric symptoms to brain structures and genetic abnormalities. (This table is in no way exhaustive but aims to show some of the neurological bases to hitherto psychiatric symptoms)
| Psychiatric symptoms | E.g. Traditional psychiatric explanation | E.g., Neural correlates | Source |
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| Depression | Narcissistic | Limbic-cortical dysregulation | Mayberg (1997) | | Obsessive Compulsive Disorder | Poor maternal parenting | frontal-subcortical circuitry, right caudate activity | Saxena et al (1998), Gamazo-Garran, Soutullo and Ortuno (2002) | | Schizophrenia | Narcissistic/Poor maternal parenting/escapism/ unresolved feelings of homosexuality | NMDA receptor activation in the human prefrontal cortex | Ross et al (2006) | | Visual hallucination | - | retinogeniculocalcarine tract, ascending brainstem modulatory structures | Mocellin, Walterfang, Velakoulis, 2006 | | Auditory hallucination | - | frontotemporal functional connectivity | Shergill et al, 2000 | | Eating disorder | Poor maternal parenting | Atypical serotonin system, right frontal and temporal lobe damage | Kaye et al (2005), Uher and Treasure (2005) | | Bipolar disorder | Narcissistic | Prefrontal cortex and hippocampus, anterior cingulate, amygdala | Barrett et al (2003), Vawter, Freed, & Kleinman (2000) |
Improved patient care
Further, it is argued that this nexus will allow a more refined nosology of mental illness to emerge thus helping to improve remediation and rehabilitation strategies beyond current ones that lump together ranges of symptoms. However, it cuts both ways: traditionally neurological disorders, like Parkinson’s disease, are being recognized for their high incidence of traditionally psychiatric symptoms, like psychosis and depression (Lerner and Whitehouse, 2002). These symptoms, which are largely ignored in neurology (Yudofsky and Hales, 2002), can be addressed by neuropsychiatry and lead to improved patient care. In sum, it is argued that patients from both traditional psychiatry and neurology departments will see their care improved following a reuniting of the specialties.
Better management model
Schiffer et al (2004) argue that there are good management and financial reasons for rapprochement.
The case for maintaining the separation of neurology and psychiatry
No psychiatric disorder has been completely "mapped"
The fact that no complete syndrome has been mapped in the brain or genome is used to suggest that psychiatric disorders are not bona fide and should thus be kept separate (e.g. Baughman and Hovey, 2006). On this issue, it is worth remembering that research into the neural correlates of psychiatric disorders is in its infancy: the answers may still be to come. One reason why they may not have been found so far is that complex mental disorders may result from minute and intricate brain-wide damage and complicated gene-environment interactions, which are only beginning to be understood. Disorders may not exist as tidy, localized neurodysfunction or genetic abnormalities but multi-factorial brain-wide disorders with complex interactions between environment and genetics E.g Green (2001). Such distributed dysfunction may not be resolvable in the living brain with current technology. E.g. disparate behavioral disorders have been linked to identical neurodysfunction with imaging but show significant organic differences following neurohistological analysis (Rempel–Clower et al, 1996). Where physiopathology is extremely small and distributed or neural tissue is actually healthy it may be the disturbed information-processing that should be studied. E.g. Bell, Halligan and Ellis' (2006) work on cognitive deficits in delusions.
Pragmatic issues
The extent to which neuropsychiatry is practically possible has been questioned. As Sachdev (2005) has noted psychiatrists and neurologists operate very different patient management strategies, which are skills honed by years of experience:
- Neurologist: Clinical examination skills; Empiricism; Objectivity; Surgery
- Psychiatrist: Rich description of mental phenomena, Well developed interviewing skills; Understanding multiple causation; Appreciation of individual differences;
Interpersonal context; Psychological and behavioral therapies
Sachdev suggests to join them may be to dilute them both. Further, the ability to maintain a competent knowledge and skill base for both neurology and psychiatry with the advent of the inexorable increase in scientific knowledge may not be possible.
Summary of the arguments for neuropsychiatry
Diseases of the body have a physical manifestation that can often be caused by internal factors, external factors, or a combination of the two. Mental disorders should be no different and when together neurology and psychiatry’s aim was to show that this was the case. Psychiatry departed the union preferring ideology over empiricism, including very environmentally-based aetiology as well as espousing that the mind was something fundamentally different from the brain. Neurologists, however, finding no physiopathology for certain disorders left them to the psychiatrists, whilst themselves pursuing the diseases with clear physiopathology.
However, the cleavage between mind and brain and the causal dichotomies are argued not to be veridical. Psychiatric disorders are increasingly showing organic manifestation and demonstrate causation from something as distant as culture. Thus the reasons for the initial division are argued not to be useful or real ones. The two specialties are both dealing with disorders of the same system. Biological psychiatry and behavioural neurology show how the boundaries are being blurred. It is argued that there can be no objection to a reunion on philosophical or scientific grounds. However, there may be reasons to question whether neuropsychiatry would be practically possible. The differences in patient management, knowledge base and skill competency between neurology and psychiatry mean that being proficient in both may be impossible.
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