Electronic self-monitored morning depression scores are related to sleep timing and sleep length in depressed patients

The relationship between depression symptoms and sleep in major depressive episodes (MDE) is complex. In this trial, 103 patients with a MDE entered morning and evening depression scores (0-10; 10 = no depression) and sleep parameters in an electronic system for 28 days after discharge from inpatient wards. Mean diurnal variation (difference between evening and morning depression scores) was 0.33 (SE = 0.10; p = 0.0009) with very large day-to-day variations. Morning depression symptoms were associated with length of sleep period in a non-linear association, with least depression symptoms at 8 h of sleep increasing for longer and shorter sleep time (p = 0.04). Morning depression symptoms were also found to increase with a later sleep midpoint (p < 0.001), a delay in sleep onset (p = 0.0001) and wakeups (p < 0.0001). In conclusion, a long and short sleep duration, late sleep-timing, sleep onset delays and wakeups, were associated with more morning depression symptoms. These explorative results should be investigated in Randomized Clinical Trials (RCTs), to test the casual relation and if confirmed, be used clinically in depression treatment to qualify the use of methods working on sleep timing and sleep maintenance like Cognitive Behavioural Therapy for insomnia (CBT-I). Trial Registration ClinicalTrials.gov NCT02679768; https://clinicaltrials.gov/study/NCT02679768 .