Season of birth and mood seasonality in late childhood and adolescence.

A significant season of birth effect on mood seasonality has been detected in young adults, with higher sensitivity to seasonal changes for people born during spring or summer months (long photoperiod) than those born during autumn or winter months (short photoperiod). The aim of this study was to verify whether the birth season effect on mood seasonality is already present in late childhood and adolescence. To this end, the Seasonal Pattern Assessment Questionnaire for Children and Adolescents (SPAQ-CA) was administered to 1523 Italian participants (870 females, 653 males), ranging from 10 to 17 years of age. The Global Seasonality Score (GSS) was computed as a measure of mood seasonality. Analysis of covariance showed a significant season of birth effect on GSS; although no comparisons were significant when Tukey's posthoc test for unequal samples was performed, it was observed that adolescents born in summer achieved the highest scores while those born in winter obtained the lowest. The present data point out that a significant season of birth effect on mood seasonality is already present in late childhood and adolescence.