Psychiatry is, in a number of ways, a unique area within medicine. It is a subject of intense public interest, with a wide-ranging influence on non-medical culture; its practitioners have a perplexing variety of strategies of diagnosis and treatment, the diversity of which can be attributed to the lack of understanding of the physical basis of mental disease. It is argued here (using schizophrenia as a particular example) that the special nature of the signs and symptoms of psychiatric disorders, involving mainly behavioural disturbances, and alterations of thought and mood, have led to particular social, even political, attitudes towards the mentally ill, to the segregation of psychiatry as a medical discipline and to a view of the disease process different from that operating in other areas of medicine. The future progress of psychiatry, both in science and in society, might depend on changes of attitude among psychiatrists themselves.