Sleep-wake patterns and their influence on school performance in Portuguese adolescents

OBJECTIVE: To characterise sleep-wake patterns and their influence on academic performance for a sample of Portuguese adolescents. RESEARCH DESIGN: Cross-sectional, analytical-explanatory, correlational epidemiological research. The protocol includes the composite morningness questionnaire (Barton et al, 1985 adapted by Silva et al, 1985), the Epworth Sleepiness Scale (Murray, 1991), chronic fatigue scale (Smith et al, 1995), the Pittsburgh Sleep Quality Index (Buysse, 1988), Educational Achievement (Fermin, 2005), personal and academic data. PARTICIPANTS: 2094 students (55.3% girls; 16–23 years old; M = 16.82 ± 1.25) attending secondary school in central Portugal. Living in urban areas, living with their parents and about 57.1% are in a family with reasonable economic resources. RESULTS: Adolescents’ sleep patterns reveal that they sleep on average between 8–9 hours a night, do not use medication to sleep, with sleep latency within the normal range, with good sleep efficiency, without daytime dysfunction and with undisturbed sleep, predominantly intermediate chronotype. Minor drowsiness, increased sleep efficiency, improved subjective sleep satisfaction, less sleep disturbance, less daytime dysfunction, not consuming hypnotic medications, associated with better academic performance. Morningness/eveningness, sleep efficiency, daytime dysfunction and sleep latency emerge as predictors of academic performance. The chronotype interacts to predict the quality of sleep enhancing it as a mediator of school performance. CONCLUSIONS: Sleep and associated individual characteristics should be considered in the diagnosis and intervention process in secondary education.