Seasonal influences on admissions for mood disorders and schizophrenia in a teaching psychiatric hospital in Egypt

Bipolar disorders: is there an influence of seasonality or photoperiod?

“…This also agrees with the international data, which indicates that bipolar disorder is one of the main causes of involuntary admission. 10,15,32 The focus of our study, however, was on analyzing admission rates during different months and seasons among the two subgroups. Seasonality has been defined as ''a driving force that has a major effect on the spatiotemporal dynamics of natural systems and their populations.''…”

“…This result underscores the higher probability of admission during the pronounced photoperiod change between spring and summer, which agrees with numerous recent studies confirming a strong seasonal pattern in bipolar disorder. [9][10][11][12][13][14][15][16]21,[34][35][36][37] This finding, in light the DSM-5's focus on seasonal pattern in bipolar disorder, prompted the following question: is seasonality really the most incisive clinical parameter for assessing the onset of bipolar disorder, or is it, rather, greater exposure to sunlight?…”

“…9 Specifically, patients with (hypo)manic episodes have higher rates of hospitalization during spring and summer, when sunlight exposure (i.e., the photoperiod) is longer, 10-14 while patients with major depressive episodes are mainly admitted during the winter. 10,[15][16][17] Photoperiod is defined as the number of hours of daylight, which can influence an individual's physiology and metabolic cycles. Ideal photoperiods are approximately 14 hours in summer and 8 to 9 hours in winter.…”

“…Amr & Volpe conducted a study comparing bipolar and schizophrenic patients in terms of monthly hospitalization rates: the authors reported that sunlight exposure had no influence on schizophrenic patients, whereas different admission patterns were observed for affective recurrences (manic or depressive episode) in bipolar patients. 10 More recent studies, however, suggest that the seasonal variation in sunlight exposure is insufficient to explain circadian rhythm disruption and that other climatic variables, such as ultraviolet exposure levels, temperature, snow, rain, and light exposure during early life should be taken into consideration. [18][19][20][21] Thus, the aim of our study was to increase understanding about the influence of photoperiod variation by following a sample of Italian bipolar patients over a period of 24 months, focusing on inpatients.…”

Psychiatric hospitalizations for affective disorders in Warsaw, Poland: Effect of season and intensity of sunlight

“…The most commonly reported finding is a rise in mania admissions in the spring and summer months (Hare and Walter, 1978;Myers and Davies, 1978;Mulder et al, 1990;Takei et al, 1992;Suhail and Cochrane, 1998;Lee et al, 2007;Amr and Volpe, 2012) and a drop during wintertime (Myers and Davies, 1978;Lee et al, 2007;Amr and Volpe, 2012). Another frequent finding is that winter (Modai et al, 1994;Suhail and Cochrane, 1998;Avasthi et al, 2001;Lee et al, 2007;Amr and Volpe, 2012), as well as spring and autumn (Eastwood and Stiasny, 1978;Frangos et al, 1980;Silverstone et al, 1995;Morken et al, 2002) are the seasons when depressive episodes appear more often.…”