Objective and subjective sleep in patients with non-seasonal major depressive disorder and eveningness - Results from a randomized controlled trial of bright light therapy.

STUDY OBJECTIVES: This study examines the (dis)agreement between objective and subjective sleep and their prospective changes in a randomized controlled trial of bright light therapy (BLT) in patients with major depressive disorder (MDD) and eveningness. METHODS: A total of 93 adults were randomized to receive either 30-min daily of 10,000 lux BLT or 50lux placebo dim red light therapy (DRL group) for a total of 5 weeks. Actigraphic data were collected at the baseline and during the last week of treatment. (Dis)Concordance of diary and actigraphic sleep parameters were assessed by partial correlations and Bland-Altman plots, and the associations between these discrepancies to depression severity was assessed by linear regression models. Changes of sleep parameters were assessed by linear mixed models. RESULTS: Significant correlations were found between subjective sleep timings and chronotype to actigraphic parameters. Discrepancies between diary- and actigraphic-measures were observed, and patients with more severe depressive symptoms were associated with a greater under-estimation of total sleep time (TST). A greater advance in the diary-based time to fall sleep and rise time were achieved in the BLT group as compared to the DRL group, while diary-based wake after sleep onset (WASO), TST and sleep efficiency (SE) comparably improved with time in both groups. There was no significant difference between the two groups in the actigraphic parameters after treatment. CONCLUSIONS: In this study, we found that depression severity influenced subjective report of sleep. BLT led to a greater advance in subjective sleep timings when compared to the placebo group.

Adjunctive bright light treatment with gradual advance in unipolar major depressive disorder with evening chronotype - A randomized controlled trial.

BACKGROUND: Unipolar non-seasonal depressed patients with concomitant evening chronotype were associated with poor clinical outcomes and higher non-remission rate. This study aims to examine the efficacy of adjunctive bright light therapy with gradual timing advance in a randomized, assessor and prescriber-blinded controlled trial. METHOD: Participants were randomly allocated to receive 5 weeks of either bright white light therapy (BLT) or dim red light (DRL) with the same advancement protocol. Participants were followed up till 5 months after treatment. Primary outcomes included (i) remission rate and (ii) the severity of depression. The analysis was conducted using Kaplan-Meier survival analysis, Cox proportional hazard analysis and linear mixed models. RESULTS: A total of 93 participants (46.4 ± 11.7 years old, 80% female) were randomized. The cumulative remission rate for the BLT and the DRL groups was 67.4% and 46.7%, respectively. Time to remission was shorter for the BLT group relative to the DRL group (log-rank test p = 0.024). Cox proportional hazard survival analysis showed that patients in the BLT group had a higher probability of achieving remission relative to patients in the DRL group [hazard ratio = 1.9 (95% CI = 1.1- 3.4), p = 0.026]. Further sensitivity analysis demonstrated greater improvement in 17-Hamilton Depression Score (group × time interaction, p = 0.04) in the BLT group for those who were adherent to light therapy. CONCLUSIONS: The use of bright light therapy with gradual advance protocol is an effective adjunctive treatment resulting in quicker and a higher rate of remission of depression in patients with non-seasonal unipolar depression and evening-chronotype.