Gender and the use of neuroleptics in schizophrenia

The oestrogen hypothesis proposes that the lower need for neuroleptic drugs in female schizophrenia patients is caused by the antidopaminergic effect of oestrogens, and that when oestrogen production decreases at menopause, the need for neuroleptic drugs increases in female schizophrenia patients.

The oestrogen hypothesis was tested in a sample of 4338 schizophrenia patients (DSM III R), who were discharged from hospital and followed up for 3 years. Prescribed daily doses of neuroleptics (DDN) were recorded and converted to chlorpromazine equivalents.

Males had higher DDN than females. When the age at first admission (AFA) was controlled, DDNs were higher in males than in females in all age groups. In addition to AFA, DDNs were associated with duration of illness (DUI), education, smoking and clinical status as well as with concurrently prescribed antidepressants, anti-manics, sedatives and hypnotics, but these factors did not explain the gender differences in DDN.

The results did not support the original oestrogen hypothesis. It is proposed that testosterone secretion may explain why male schizophrenia patients are prescribed higher DDNs than female patients. Ageing processes in the central nervous system (CNS) may explain why DDNs decrease after middle age in both genders.