Seasonality of the episodes of recurrent affective psychoses. Possible prophylactic interventions.

This study is an attempt to ascertain whether evidence for seasonal variations of the episodes of recurrent affective psychoses can be found in patients in Greece. Due allowance has been made for the fact that different socio-cultural and above all climatological factors prevail in Greece as opposed to other countries, which might be relevant in the phenomenon of seasonality. The seasonal distribution of the psychotic episodes, either depressive or manic, has been examined for 533 patients with various forms of affective psychoses, admitted to and treated in the State Mental Hospital of Athens, Greece, during the last 50 years. Statistically significant seasonal variation with peaks in spring was found for both depressive and manic episodes of various subgroups of patients, divided according to the I.C.D.-9.