Psychological deterioration, defect state and psychological deficit are all terms introduced this century to replace Kraepelin's idea of dementia praecox. They all express the notion that schizophrenics have some global impairment in psychological functioning, which is different from the presenile dementias or recognised causes of cerebral dysfunction. At the beginning of the century it was generally regarded as organic in nature. In the 1960s the social revolution in psychiatry encouraged the view that the deterioration was psychosocial, the effect of institutionalisation. There has been a recent trend to revive the organic formulation.

The five articles which follow examine the idea from different points of view. They were commissioned because correspondence to the editor indicated that the issue was topical and controversial. It is hoped that they may be the first of a series of multi-author contributions on topical issues.

Manfred Bleuler presents his view that deterioration is not a progressive condition, but one of several outcomes, and even then liable to remission. Luc Ciompi discusses the relationship between organic and psychosocial factors in its cause, and concludes that it is the result of an interaction between the two. Tim Crow gives a clear account of the organic model. David Abrahamson draws attention to some methodological issues, which have led to a false clinical impression, and wrongly overemphasised the extent of deterioration. Digby Tantam analyses the complex effect of drug treatment.