Psychiatry is a branch of medicine with a relatively short history. Although mental illness has probably existed throughout the history of mankind, it has received little attention from the medical perspective. Major psychoses have been considered as either spiritual or functional until recently. The functional or organic dichotomy has been the official watershed dividing the disciplines of Neurology and Psychiatry.
While Neurology follows the basic medical approach, Psychiatry takes a much broader, and perhaps more diffuse, perspective. During the past few decades, there has been a quantum leap in the volume of basic neuroscientific research. A much better understanding of the neural mechanisms underlying most, if not all, psychiatric disorders has led to a revolutionary change in the concept of mental disorders. Most functional or psychogenic problems have now been found to have an 'organic' aetiology. Functional psychiatric disorders are much better perceived as medical disorders leading to disturbances in brain function. Clinical manifestations are disturbances of the integration between mood, perception, and thought processes. The old distinction between diseases as either neurological or psychiatric faces challenges to its validity. It would be over-simplistic to assume that brain disorders will manifest either along the neurological or psychiatric dimension, and be managed with a single approach.
In this issue, the significance of a combined neuropsychiatric approach to the assessment and management of brain disorders is highlighted. The article on depressive disorders in Parkinson's disease (PD) underscores the prevalent psychiatric co-morbidity in this classical neurological disorder. (1) Discovery of degeneration of the dopaminergic system in this disorder led to the development of an associated treatment. It is well-recognised that PD is readily amenable to pharmacological interventions that bolster dopaminergic transmission. Nevertheless, the focusing of attention on the motor symptoms of PD is associated with a neglect of other important determinants of quality of life, such as depressive disorders and other psychopathology. The report on mitochondrial encephalopathy, lactic acidosis and stroke-like syndrome (MELAS) provides an excellent example of the complex neuropsychiatric manifestations of a rare metabolic brain disease. (2) In MELAS, a combination of neurological and psychiatric symptomatology, and use of sophisticated neuroimaging and laboratory technology are required to make the diagnosis.
It is perhaps meaningless to argue about the importance of paying dual attention to the neurological and psychiatric aspects of brain disorders. A more intriguing question may be the need for a division between Psychiatry and Neurology, or more specifically, the distinction between Behavioural Neurology and Neuropsychiatry. …