Type D personality is associated with sleep problems in adolescents. Results from a population-based cohort study of Swedish adolescents

Objective: Sleep problems are associated with an increased risk of psychiatric and somatic diseases. Type D personality, or the distressed personality, refers to the joint tendency to experience negative emotions and to inhibit self-expression in social interaction. Type D personality is associated with an increased number of health complaints including cardiovascular diseases. The present study investigated whether Type D personality was associated with sleep problems among adolescents. Methods: The study was part of the Survey of Adolescent Life in Vastmanland 2008 (SALVe 2008). A total of 5012 adolescents (age 15-18 years old) completed a questionnaire including the Type D measurement DS14 and questions on sleep disturbances, sleep hours during school nights, and sleep hours during weekend nights. Results: Adolescents with a Type D personality had an approximately four times increased risk of having sleep disturbances. Moreover, Type D personality was associated with sleeping fewer hours. Conclusion: As adolescence represents a formative period for development it is critical to identify sleep disorders early. The presence of Type D personality associated with poor sleep demands attention because sleep problems may be an early stage in the development of later diseases. (C) 2012 Elsevier Inc. All rights reserved.