The initial dose of fluoxetine 20mg was taken after the first time in bed condition night, followed by fluoxetine 20mg/day for 8 weeks. Based on clinician-rated response, dose could be increased to 40mg after week 4.
Symptom severity was rated at baseline and then weekly by clinicians blinded to the time in bed condition. Primary outcome measures, as rated by the 17-item Hamilton Depression Rating Scale, were symptom severity, remission rates, and remission onset. Compliance was evaluated by pill count at each in-laboratory visit.
Study subjects also completed depression scales at baseline and at weeks 1, 2, 4, and 8; quality-of-life ratings were completed at baseline and weeks 4 and 8.
A total of 58 subjects (85.2%) completed the 2-week time in bed condition and 54 (79.4%) completed the 8-week study. Among those randomly assigned, 11 (16.2%) discontinued participation, 3 in the 8-hour, 5 in the late bedtime, and 3 in the early rise time groups; in addition, 4 subjects were discontinued for protocol violations.
When the 8-hour time in bed group was compared with both 6-hour time in bed groups, lower depression severity was observed in the 8-hour group (P<.05). Among those in the 8-hour group, 63.2% remitted by week 8, compared to 32.6% of subjects in the 6-hour groups, and this remission occurred earlier (hazard ratio = 0.43; 95% CI, 0.20-0.91; P<.03). No difference in remission onset was seen between the 6-hour time in bed conditions.
The Self-Rated 12-Item Short-Form Health Survey indicated a significant difference between the 8-hour time in bed and 6-hour time in bed groups in the mental composite score at Week 8 compared to baseline (–7.9; P = .04).
These findings “raise the possibility that adequate time in bed duration may positively impact treatment response,” they reported, adding that “these effects were not due to better medication compliance or to a higher medication dose in the 8-hour time in bed group. Importantly, objective compliance monitoring indicated that subjects were compliant with the 8-hour time in bed schedule, but subjects assigned to the 6-hour time in bed schedule were not. To our knowledge, this study is the first to evaluate experimentally a modest repeated time in bed restriction in antidepressant treatment response.”
Needed to confirm these finding are studies that “optimize or extend sleep duration while initiating antidepressant therapy,” including in “larger, more ethnically diverse, and older samples.” In addition, diurnal mood variation and circadian preference or insomnia, potentially important clinical and sleep-related moderators, respectively, should be systematically included in studies to measure treatment response and evaluate mechanisms of adjunctive treatments for depression.
The authors concluded: “Patients initiating a new trial of antidepressant medication should be cautioned against restricting their time in bed.”
1. Arnedt JT, Swanson LM, Dopp RR, et al. Effects of restricted time in bed on antidepressant treatment response: A randomized controlled trial. J Clin Psychiatry. Dx.doi.org/10.4088/JCP.15m09879.