Enfermedades afectivas y actividad solar: Seguimiento a 16 años / Association between hospital admissions due to affective disorders and solar activity: Analysis of 16 years

ABSTRACT

Background: Exposure to solar activity may be associated with incidence of depressive and manic disorders. Aim: To assess the link between solar activity and appearance of affective disorders. Material and Methods: We examined 1862 clinical records of a psychiatric clinic located in Santiago, Chile. Patients with major depression and manic disorders were included in the study, only when they were admitted at the clinic for the first time. Solar activity was calculated using the Wolf number, which is given by the formula R= K(10g+f), where “g” stands for the groups of sunspots and “f ” is the total number of sunspots. We examined the correlation between annual incidence of hospital admissions and average Wolf numbers for the period 1990-2005, which corresponds to approximately one and half solar cycles of 16 years. Results: A total of 450 medical records corresponding to 299 patients (199 women) with depressive symptoms and 151 patients (73 women) with mania, were analyzed. There was a higher number of admissions for depression during the years with lower solar activity. Admissions due to mania tended to increase in the years with high solar activity. There was a negative correlation between the number of hospital admissions due to depression and solar activity (Spearman r =-0.812, p < 0.01). The association between the latter parameter and admissions due to mania did not reach statistical significance. Conclusions: There is a significant negative association between the rate of hospital admissions due to depressive disorders and solar activity.