DELAYED SLEEP PHASE SYNDROME. PREVALENCE, DEVELOPMENTAL HISTORY, PERSONALITY AND TREATMENT

Delayed sleep phase syndrome (DSPS) is a circadian rhythm sleep disorder assumed to peak in adolescence and young adulthood. It is characterized by a delay in the sleep wake-rhythm which causes prolonged sleep onset latency and problems getting up in the morning. The disorder often has negative impact on work, school and leisure activities. Little research has been conducted regarding this disorder. The present project comprises four studies: Study1: The Bergen Child Study is a longitudinal epidemiologi cal study conducted in three phases comprising all children in 2.-4. grade in the Bergen and Sund municipalities in 2002 (first phase). Second phase was conducted in 2006, and the third will be conducted in 2008/09. In phase 1-3 questions about sleep prob lems were included. In phase 2 questions about bed- and rise time were additionally incorporated. In phase 3 we will include specific questions about DSPS - and measure sleep with sleep diaries and interview at those at risk to obtain a valid diagnosis of DSPS. We will investigate the prevalence and identify risk factors of DSPS. Study2: 60 subjects with DSPS will be recruited and compared to 60 normal sleepers, matched for gender and age, on central personality traits based upon the five-factor model of personality. Study3: 20 patients suffering from DSPS will be subjected to a qualitative interview focusing upon the course of the disorder, coping strategies and experienced consequences of the disorder. Study4: The 60 patients will be randomized to 1 of 4 conditions: 1) bright light + melatonin, 2) placebo light + melatonin, 3) bright light + placebo pills, and 4) placebo light and placebo pills. Outcome variables comprise polysomnographic data, dim light melatonin onset, actigraphy, and reactio n time test + subjective data (sleep diary, anxiety and depression, life satisfaction). Outcomes will be measures at post-treatment (after 2 weeks) and at follow-up (after 6 months).