Bidirectional Relationship of Sleep with Emotional and Behavioral Difficulties: A Five-year Follow-up of Finnish Adolescents.

The long-term effects of sleep on adolescent psychosocial well-being are mostly unknown, although insufficient sleep has been associated with emotional and behavioral difficulties in cross-sectional studies. With a five-year follow-up of Finnish adolescents (Time 1: n = 8834; Mean age = 13 years, 51.1% female, Time 2: n = 5315, Mean age = 15 years, 51.6% female, Time 3: n = 3712; Mean age = 17 years; 50.2% female), the purpose of this longitudinal study was to investigate the relations between self-reported sleep duration, sleep problems, and emotional and behavioral difficulties during adolescence. Emotional and behavioral difficulties were assessed using The Strengths and Difficulties Questionnaire (SDQ) measuring emotional symptoms, conduct problems, hyperactivity, peer problems and total difficulties. Sleep duration was calculated by counting the hours between self-reported bedtime and wake-up time. Sleep problems were assessed with a single question about the general sleep problems. According to the cross-lagged models for sleep and emotional and behavioral difficulties, the findings of this study indicate a developmental process during adolescence where, firstly, short sleep duration is a stronger predictor for current and prospective emotional and behavioral difficulties than vice versa. Secondly, increased emotional and behavioral difficulties expose adolescents to current and later sleep problems more strongly than reverse. Thus, the results show that short sleep duration predisposed to emotional and behavioral difficulties across adolescence, which then led to more prospective sleep problems. These findings suggest a developmental process where sleep and emotional and behavioral difficulties are intertwined in shaping adolescents' health.