P051 Associations between Chronotype and Symptoms of Depression in Patients attending an Outpatient Sleep Clinic

INTRODUCTION: Chronotype (or morningness-eveningness), individuals’ time-of-the-day preference for activity, has been associated with depressive symptoms. This cross-sectional study examined the association between chronotype and symptoms of depression in outpatients attending a sleep disorders clinic. METHOD: The sample included individuals attending an outpatient sleep disorders clinic and provided opt-out consent for their data to be used for research purposes. Individuals included in the analyses provided demographic data, their typical weekly total sleep time (TST), and complete responses prior to treatment on the reduced Morningness-Eveningness Questionnaire (rMEQ; for chronotype), and the PROMIS depression scale. RESULTS: A total of 1641 (44.5% female, Mage = 45.20 years, SDage = 16.06 years) participants were included. On average, the sample scored intermediate chronotype (M = 14.73, SD = 4.35) and higher depressive symptom scores that were half a standard deviation higher compared to community norms (M = 55.80, SD = 10.01). Multiple linear regression controlling for age, sex, and TST showed that greater eveningness preferences predicted higher symptoms of depression, p<0.01, explaining 2.76% additional variance in depression scores above that of the covariates. DISCUSSION: Overall, sleep clinic outpatients had an intermediate chronotype and above average depressive symptoms. The findings are consistent with existing literature in other populations indicating that eveningness may be a risk factor for greater symptoms of depression. Future studies need to explore whether interventions to alter chronotype may benefit symptoms of depression in individuals with sleep complaints.