The Limitations of Psychiatric Diagnoses

Psychiatric disorders are not always easy to incorporate within the medical model, neuropathological changes are seldom demonstrable and, when they are, they are irrelevant to functional illnesses. The meaning of the term illness in this group is not the same as in medicine generally and the validity of each illness category depends on the internal consistency and homegeneity of the category, the lack of overlap with other categories and the inter-rate reliability, but these desiderata are not adequately met for neurotic and personality problems or alchoholism. The major division between schizophrenia and manic depressive psychosis is not as sharply delineated as might be imagined and trans-Atlantic diagnostic practices have swung from one type of divergence to another. Nevertheless an increasing number of physical findings in these disorders suggest that they are frequently underpinned by organic factors. By definition this is certainly the case for organic psychoses, including epileptic psychosis and dementia. On the other hand, alchoholism, drug addiction, psychopathy and neuroses may be better incorporated within a psychological model, although here too weaker, but still apparent, physical and genetic factors remain intriguing features for medical consideration. Nevertheless life expectancy, fertility and socioeconomic circumstances are adversely affected by most psychiatric disorders, making them genuine illnesses by such criteria.