The psychiatric aspects of tropical disorders

The nature of psychiatric disorders in tropical regions is affected much more by the effect on the patient of certain environmental and cultural factors than by any specific features of tropical diseases. In places where the standards of health care and health education are not yet fully developed, abnormalities of physical development, particularly those affecting the development of the cerebral cortex, are of great importance. For example, protein-energy malnutrition may result in deficits in cerebral maturation and efficiency that reduce the capacity of the brain to manage its behavioural functions and may give rise to impaired capacities for concentration, foresight, and judgement and impairment of inhibitory control over intensely experienced emotions. In addition, certain cultural attitudes that are widespread in pre-literate societies influence the type of secondary reaction to disease: for example, acute symptoms tend to be florid and uninhibited, and violently experienced and externalized emotions such as hilarity, terror, anger, and grief are the rule rather than the exception.Certain tropical diseases are, however, the direct cause of severe disturbance of cerebral functioning, while others affect only the finer cerebral controls so that normally controlled fears, anxieties, and other personality traits emerge. These specific brain syndromes may be acute or chronic and may be triggered by an apparently trivial physical cause. Acute brain syndromes appear to be more common in tropical countries perhaps because in the adult the cerebral cortical reserve is less than it ought to be because of the prevalence of earlier minimal brain damage. Formal psychiatric reactions are, of course, also seen in tropical countries, but the expression of, for example, schizophrenia, hypomanic and manic states, and depression is coloured by the underlying personality and the cultural background of the patient. Perhaps in no other setting is the intimate relationship between behaviour and the physical body seen more clearly than in populations living in the tropics and it is important that health workers in these regions should be aware of the role played by earlier or concurrent physical disease in behavioural disturbance.