Acute psychiatric admission and menstrual cycle phase in women with schizophrenia.
The clinical observation of a possible relation between the phases of the menstrual cycle and psychotic illness dates well back to the beginning of the nineteenth century. This relation is considered to provide further evidence for the protective effect of oestrogens in schizophrenic women and is summarised by the so-called oestrogen hypothesis. In addition, the hypoestrogenism hypothesis postulates a hypofunction of the gonads in women with schizophrenia with subsequent oestrogen deficiency syndrome. The aim of the present clinical study was to answer the question whether there is a perimenstrual increase in hospital admissions of women suffering from an exacerbation of schizophrenia. Two samples of premenopausal women with schizophrenia were investigated (sample 1: n = 115; sample 2: n = 170). In both samples there was a significant increase in admissions in the perimenstrual phase - three days before and three days after the first day of the menses (sample 1: P = 0.002, sample 2: P = 0.028, binomial test). 37.4% of the patients were admitted during the perimenstrual phase of the cycle in sample 1, 31.8% in sample 2. Regarding age, age at onset, and duration of illness, no difference was found between the group admitted to hospital during the perimenstrual phase versus the group admitted during the rest of the menstrual cycle in either of the samples. The results are discussed in relation to the possibly underlying physiological mechanisms.