Associations between sleep habits, quality, chronotype and depression in a large cross-sectional sample of Swedish adolescents.

Objective: To investigate behavioral sleep habits, self-perceived quality of sleep, and chronotype, and to examine their association with clinically relevant levels of depression in Swedish adolescents.

Method: Questionnaire data were obtained from a representative sample of Swedish adolescents (n = 8449; 50.8% girls; aged 12-16).