Introduction: The present work discusses the link between solar activity and appearance of affective disorders. Solar activity is reflected by the Wolf number, which is given by the formula R = K (10 g + f), where g corresponds to the groups of sunspots and f is the total number of sunspots.
Methods: We examined 1,212 clinical files at the Clínica Psiquiátrica Universitaria, Santiago de Chile. Patients with major depressions and manic disorders, who were admitted to the clinic for the first time and had no previous treatment were considered. We examined the correlation between annual incidence of hospitalization and average Wolf numbers for those years, included in the period 1990-2000, which corresponds to a complete solar cycle of 11 years.
Results: An important number of hospitalizations of depressive patients occurred during years of low solar activity, and there was a slight increase in the number of manic patients during years of high solar activity. Depressive disorders showed a negative correlation with solar activity, the Pearson coefficient being equal to -0.72. Manic disorders showed a positive correlation, with coefficient equal to +0.334.
Conclusions: Depressive disorders have an inverse correlation with solar activity, while manic disorders have a positive correlation.