Relationship Between Depressive Symptoms and Sleep Duration/Chronotype in Women

There are few studies suggesting that chronotype or morningness-eveningness (M/E) is a predictor of depressive symptoms. A sample of 277 women (university students) of a mean age of 22.25 years +/- (SD) 2.47 participated in this study. We used the Composite Scale of Morningness to assess circadian typology, the Patient Health Questionnaire (PHQ-9) to assess depressive symptomatology, and because M/E as well as depressive symptoms are associated with personality - we controlled for personality using a short measure of the Big Five Inventory as well as including a scale to measure hypochondriasis. There were 28 women classified with moderate, one with moderately severe, and three with severe depression. Negative correlations existed between CSM score, average sleep duration, extraversion, conscientiousness, and PHQ-9 scores, and positive correlations between hypochondriasis, neuroticism, and PHQ-9 scores. In a hierarchical regression, the model predicts 28% of variance in the PHQ-9 scores. Personality explained 15%, hypochondriasis accounted for 8%, and sleep duration and M/E added another 5%. The results suggest that the influence of morningness-eveningness (beta = -0.102) is weaker than the influence of sleep duration (beta = -0.194).