Effects of climate on admission rates of schizophrenia patients to psychiatric hospitals.

Data on admissions of schizophrenia- and schizoaffective disorder patients to Tel-Aviv's seven public psychiatric hospitals during 11 consecutive years were obtained along with relevant meteorological information. Mean monthly admission rates were significantly higher during the summer (for schizophrenia patients) and fall (for schizoaffective patients). Schizophrenia patients' mean monthly admission rates correlated with mean maximal monthly environmental temperature (R = 0.35, N = 132 months, P <0.001). The present study may indicate that persistent high environmental temperature may be a contributing factor for psychotic exacerbation in schizophrenia patients and their consequent admission to mental hospitals.

Admission rates of bipolar depressed patients increase during spring/summer and correlate with maximal environmental temperature.

OBJECTIVE: We intended to identify a relationship, if exists, between various climatic factors and the admission rates of bipolar affective disorder depressed patients (BPD) or major depressive disorder patients (unipolar) (UPD) to psychiatric hospitals, as well as potential seasonal variability in hospitalization rates of this population. METHODS: Data on admissions of ICD-9 BPD and UPD patients to Tel Aviv's seven public psychiatric hospitals during 11 consecutive years were collected along with concomitant meteorological information RESULTS: Admissions of 4117 patients with BPD and 1036 with UPD who fulfilled our specific inclusion criteria were recorded. Bipolar depressed, but not UPD, patients exhibited significant seasonal variation (higher spring and summer versus winter mean monthly admission rates), and the admission rates of patients with BPD, but not UPD, correlated significantly with mean maximal monthly environmental temperature CONCLUSIONS: Increased environmental temperature may be a risk factor for evolvement of major depressive episode in patients with bipolar disorder with psychiatric co-morbidity, at least in cases that necessitate hospitalization and at the examined geographic/climatic region of Israel. Further large-scale studies with bipolar depressed patients with and without co-morbid disorders are needed to substantiate our findings and to determine the role of seasonal and climatic influence on this population, as well as its relationship to the pathophysiology of bipolar disorder.