Spending more time in bed or asleep is associated with higher core depressive symptoms in patients with major depressive disorder (MDD), according to results published in JMIR Mental Health.
Patients with recurrent MDD who participated in the Sensor-based System for Therapy Support and Management of Depression (STEADY) study were included in this analysis (n=22). During the STEADY study, participants self-rated their depression core symptoms immediately upon waking in the morning and right before bed in the evening. Participants also self-rated their night sleep, including the time they went to bed, the time they got up, and their time spent sleeping. The sleep diary was used to calculate time in bed and total sleep time, which were used for this analysis.
On average, each patient recorded their daily sleep patterns and self-rated depression core symptoms for 173 days (range, 143-205). The mean Pittsburg Sleep Quality Index baseline score was 8.95. The majority of patients (86%) were taking antidepressant medications and had received psychotherapy, or were currently receiving psychotherapy at the time of the study.
According to Granger causality tests, there was a positive association between time spent in bed and more depression core symptoms in 3 patients. In addition, more depression core symptoms were associated with more time in bed in 3 patients. Total sleep time was also positively associated with more severe depression in 3 patients, whereas more depression core symptoms were positively associated with greater total sleep time in 2 patients. A 1 standard deviation change in depression core symptoms resulted in a significant increase in bed time the following 2 days. At day 2, there was an increase of 12.86 minutes spent in bed.
Limitations of the analysis included the small sample size as well as the self-reported nature of the sleep data.
The researchers wrote that if further “data suggest that a longer time in bed worsens depressive symptoms, therapeutic sleep restriction or long-term mild sleep restriction might be a promising intervention” for patients with MDD.
Lorenz N, Sander C, Ivanova G, Hegerl U. Temporal associations of daily changes in sleep and depression core symptoms in patients suffering from major depressive disorder: Idiographic time-series analysis. JMIR Ment Health. 2020;7(4):e17071.