Morningness/eveningness and school performance among Spanish adolescents: Further evidence

Adolescents shift their time of day preferences from morning to evening during puberty when school schedule becomes earlier. Given that a better performance is obtained when individuals are tested at times that are in synchrony with their chronotype, and optimal sleep duration is positively associated with academic performance, evening-types may obtain worse school performance because of both morning school schedule and a decrease of total sleep time. A group of 1133 adolescents (aged 12-16) participated in this study. School performance was evaluated using subjective level of achievement and self-reported grades measures. Controlling for total sleep time, more evening oriented young adolescents (12-14 years) performed significantly worse in school achievement. Girls among 15-16 years performed significantly better than boys. These results have important implications for intervention and prevention programs during school years. (C) 2011 Elsevier Inc. All rights reserved.