Objective: The role of environmental factors in hospitalization of patients with schizophrenia is incompletely understood. This study attempts to relate the pattern of hospital admissions to environmental variables such as season and to social factors such as nationally celebrated holidays.
Methods: Charts of all adults (n = 4,331) with a discharge diagnosis of schizophrenia admitted to the Abarbanel Mental Health Centre (Bat Yam, Israel) between 1 January 2001 and 31 December 2005 were reviewed. Hospitalizations were classified by gender, first or repeat admission, month and season of admission, and whether or not the admission coincided with a major Jewish holiday period.
Results: There was a significant reduction (p < 0.05) in first admissions for men during April, the month corresponding to Passover, the most widely celebrated holiday in Israel. This pattern was not seen for women or for repeat admissions. There was no significant effect of the season upon admission rates, using two different methods of defining the season.
Conclusions: This study demonstrated significant monthly variability in admission rates and a possible protective effect of a widely celebrated public religious holiday. A consistent effect of season upon rates of admission was not found. Future studies need to identify which specific social factors exert a protective or harmful effect and study how knowledge of these effects can be translated into clinical practice.