Free Online Book from PSYPLEXUS - a portal for mental health professionals

AUTHOR: DR. SHAHUL AMEEN, M.D.

1. INTRODUCTION

DEFINITION OF “ORGANIC MENTAL DISORDERS”

During the past few decades, the advent of newer pharmacological treatments and advances in fields such as neuroimaging, genetics, and molecular biology, have resulted in a growing recognition of brain pathology as the basis for mental disorders. Indeed, the introduction to the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition Text Revision (DSM-IV-TR; American Psychiatric Association, 2000) agrees that the term “mental disorder” unfortunately implies a distinction between “mental” disorders and “physical” disorders that is a reductionist anachronism of mind / body dualism, and admits that the term “mental disorder” persists in the title of the Manual because an appropriate substitute have not been found.

The term "organic," as used for many years pointed to defined pathological lesions and was contrasted with the term "functional" or physiological abnormalities that could not be detected by existing laboratory procedures. The DSM-IV (American Psychiatric Association, 1994) and DSM-IV-TR abandon the categories of organic and functional mental disorders. DSM-IV introduced the category Mental Disorders due to a general medical condition to designate psychopathological syndromes which are known to be symptomatic manifestations of a systemic medical or cerebral disorder. Disorders are included in this category if they meet the following criteria: (1) There is evidence from the history, physical examination, or laboratory findings that the disturbance is the direct physiological consequence of a general medical condition; (2) The disturbance is not better accounted for by another mental disorder; (3) The disturbance does not occur exclusively during the course of a delirium. The term general medical condition refers to conditions that are coded on Axis III and are listed outside the “mental disorders” chapter of ICD (American Psychiatric Association, 2000).

ICD – 10 maintains "organic" as a superordinate category. The block F00 – F09 is titled “Organic, including symptomatic, mental disorders”, and comprises “a range of mental disorders grouped together on the basis of their common, demonstrable etiology in cerebral disease, brain injury, or other insult leading to cerebral dysfunction” (World Health Organization, 1992). ICD-10 indicates that the dysfunction may be primary, as in diseases, injuries and insults that affect the brain directly or with predilection, or secondary, as in systemic disorders that involve the brain. ICD-10 uses the term symptomatic for those organic disorders in which cerebral involvement is secondary to a systemic extracerebral disease or disorder. ICD-10 states that use of the term “organic” does not imply that conditions elsewhere in the classification are “nonorganic” in the sense that they have no cerebral substrate, and that the term means simply that the syndrome so classified can be attributed to an independently diagnosable cerebral or systemic disease. ICD-10 recommends four criteria for classifying a syndrome as organic: (1) evidence of cerebral disease, damage, or dysfunction, or of systemic physical disease, known to be associated with one of the listed syndromes; (2) a temporal relationship (weeks or a few months) between the development of the underlying disease and the onset of the mental syndrome; (3) recovery from the mental disorder following removal or improvement of the underlying presumed cause; and (4) absence of evidence to suggest an alternative cause of the mental syndrome (such as a strong family history or precipitating stress).

Neuropsychiatry: the Interface of Psychiatry and Neurology

Neuropsychiatry is defined as "a field of scientific medicine that concerns itself with the complex relationship between human behavior and brain function, and endeavors to understand abnormal behavior and behavioral disorders on the basis of an interaction of neurobiological and psychological–social factors" (International Neuropsychiatric Association, 1998). Neuropsychiatry is sometimes seen as an umbrella term for a number of closely related fields that are slightly different in focus and scope. Biological psychiatry is an academic field involved in research related to understanding the biological basis of various psychiatric conditions. Cognitive neuroscience entails developing cognitive models for various psychiatric symptoms and conditions and then relating them to brain function. Behavioural neurology is a relatively new but rapidly developing field of neurology, which attempts to find a neurological explanation for behavioural disturbances. Organic psychiatry is another umbrella term for neuropsychiatry related fields (Agrawal, 2004).

In the 18th and 19th centuries eminent clinicians and researchers working in neurosciences were in fact neuropsychiatrists - they were working with disorders of the brain, which included both neurological and psychiatric disorders. The 20th century, however, saw a gradual separation of Psychiatry and Neurology. The focus of Psychiatry shifted gradually from structural neuropathology to psychoanalysis and then to community and social psychiatry (Sabshin, 1990). Neurology and psychiatry have, for much of the past century, been separated by an artificial wall created by the divergence of their philosophical approaches and research and treatment methods. Scientific advances in recent decades have made it clear that this separation is arbitrary and counterproductive (Martin, 2002). Neurologic and psychiatric researches are moving closer together in the tools they use, the questions they ask, and the theoretical frameworks they employ; and Neuropsychiatry is reemerging as an integrating conceptual focus for both psychiatrists and neurologists.

Other features in PsyPlexus: