There are no commercial associations related to any of the authors that might pose a conflict of interest in connection with the manuscript.
Admission rates of bipolar depressed patients increase during spring/summer and correlate with maximal environmental temperature
Article first published online: 3 FEB 2004
Volume 6, Issue 1, pages 90–93, February 2004
How to Cite
Shapira, A., Shiloh, R., Potchter, O., Hermesh, H., Popper, M. and Weizman, A. (2004), Admission rates of bipolar depressed patients increase during spring/summer and correlate with maximal environmental temperature. Bipolar Disorders, 6: 90–93. doi: 10.1046/j.1399-5618.2003.00081.x
- Issue published online: 3 FEB 2004
- Article first published online: 3 FEB 2004
- Received 30 December 2002, revised and accepted for publication 4 August 2003
- bipolar affective disorder;
- environmental temperature;
- major depressive disorder (unipolar);
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.