Study design
- Investigators conducted a systematic review of RCTs of BLT for patients with bipolar depression. Articles were obtained from Web of Science, Embase, MEDLINE, PsycInfo, and Clinicaltrials.gov using the search terms “light therapy,” “phototherapy,” “light treatment,” and “bipolar.”
- Inclusion criteria required patients diagnosed with bipolar disorder currently experiencing a depressive episode, a clinician-rated measure of depressive symptomatology, a specific light intervention, and a randomized trial design with a control.
- A total of 7 RCTs with 259 participants were reviewed. The primary outcome was improvement in depressive symptoms based on the 17-item HAM-D.
Outcomes
- BLT was associated with a significant improvement in clinician-rated depressive symptoms (P = .03).
- Data for clinical response obtained from 6 trials showed a significant difference favoring BLT vs control (P = .024). Data for remission obtained from 5 trials showed no significant difference between BLT and control (P = .09).
- Compared with control, BLT was not associated with an increased risk of affective switches (P= .67).
Conclusion
- This study suggests a small to moderate but significant effect of BLT in reducing depressive symptoms.
- Study limitations included inconsistent light parameters, short follow-up time, small sample sizes, and the possibility that control conditions had treatment effects (eg, dim light as control vs no light).
3. Hirakawa H, Terao T, Muronaga M, et al. Adjunctive bright light therapy for treating bipolar depression: a systematic review and meta-analysis of randomized controlled trials. Brain Behav. 2020;10(12):ee01876. doi.org/10.1002/brb3.1876
Hirakawa et al14 assessed the role of adjunctive BLT for treating bipolar depression. Previous meta-analyses focused on case-control studies that assessed the effects of BLT and sleep deprivation therapy on depressive symptoms, but this meta-analysis reviewed RCTs that did not include sleep deprivation therapy.
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