Objective: The aim of this study was to further evaluate the oestrogen hypothesis of schizophrenia, which postulates low oestradiol levels to be a risk factor for these disorders. A possible influence of neuroleptic-induced hyperprolactinaemia was to be addressed.
Method: Sex hormones were measured and cycle phase assessed in 50 acutely psychotic women on admission and for four consecutive weeks as well as in three control groups.
Results: Psychotic women were more likely to be admitted during a low oestrogen phase of their cycle and exhibited markedly reduced oestradiol levels, compared with 23 healthy controls, as well as 50 women suffering from other psychiatric disorders. Oestradiol variability was reduced over the menstrual cycle in women suffering from psychotic disorders.
Conclusion: These results support the oestrogen hypothesis. Hyperprolactinaemia due to neuroleptic treatment does not appear to account for the findings.