The seasonality of birth dates of schizophrenic and bipolar patients has
been studied extensively. The moon cycle, another rhythmical influence,
is unfoundedly believed to affect mental health. This pilot study investigated
a possible relationship of the moon cycle with birth dates of schizophrenic
and bipolar in-patients. Schizophrenic births peaked 5 days after and on the day of full moon. Bipolar births peaked 3 days after and on the day of full moon. These results suggests a statistical dependency between the moon cycle and birth dates of these patients and possible implications are
discussed. Epidemiological verification of this relationship is required.