Daylight saving time in psychiatric illness.

It has been reported that the change in photoperiod induced by the occurrence of daylight saving time has an effect on psychiatric presentation. We therefore investigated the impact of daylight saving time in three conditions: (1) parasuicide presentations; (2) psychiatric outpatient contacts, and inpatient admissions; (3) registered suicides. Results indicate that neither the change in photoperiod nor the effect of a small change in circadian rhythm associated with daylight saving time has an effect on 'cases' in any of the three conditions.