Schizophrenia: a review of diagnostic and biological issues. II. Biological issues.

Over the years schizophrenia has been the object of an extensive amount of research. In Part I of this paper, published in the April H&CP, the authors discussed research into diagnosis and prognosis. In particular, they outlined the studies that have been done on the major diagnostic systems, including the first-rank symptoms, the flexible system, the New Haven Schizophrenia Index, the Feighner criteria, the Research Diagnostic Criteria, and the Diagnostic and Statistical Manual of Mental Disorders, third edition. In part II they describe the literature on biological issues in schizophrenia. Included in their survey are the studies on neuropathological issues and on genetic and biological hypotheses of etiology and pathogenesis. In particular they discuss the possible roles of dopamine, endorphins and neuropeptides, endogenous psychotomimetics, and viruses in schizophrenia.