A documentary survey of a national sample of males aged 25-34 on their first admission to a mental hospital in England and Wales for schizophrenia showed the usual excess of patients in social class V. However, the social class distribution of the fathers at the time of the patients' birth was very similar to that of the population as a whole. A clinical study of a representative series of consecutive admissions of male schizophrenics aged 15-30 living in a socially mixed area in outer London confirms these findings. It shows decline in occupational status both from father to son and in the patients' own history.

The main evidence of individual downward "drift" is the ability of schizophrenic patients to win places at grammar schools, though they end in semi- or unskilled jobs. The employment histories showed that in their adolescence many patients pursued varied careers, a considerable proportion aiming at professional or technical jobs; they still fitted broadly with the career expectations of their home environment.

The discrepancies in social performance between father and son could be mainly attributed to the disease process. Patients whose illness had an insidious onset at adolescence did not attain any professional or technical skill; those whose illness started acutely before admission dropped in social class shortly before admission; while those who were mentally subnormal as well as schizophrenic did not achieve any level of skill at all.

This social drift appears to affect the highest and lowest social classes most severely. Only one patient out of 13 grammar school boys attained social class I or II status, and over half of those in social class V had dropped out of the labour market by the end of the survey. On the other hand, two-thirds of the patients in social classes III and IV survived in jobs requiring a moderate degree of skill.

These findings suggest that gross socio-economic deprivation is unlikely to be of major aetiological significance in schizophrenia. On the other hand, occupational factors, yet to be defined clearly, appear to exert some influence on the course of the disease.