Light Therapy for Patients With Bipolar Depression: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Raymond W. Lam*, Minnie Y. Teng, Young Eun Jung, Vanessa C. Evans, John F. Gottlieb, Trisha Chakrabarty, Erin E. Michalak, Jill K. Murphy, Lakshmi N. Yatham, Dorothy K. Sit

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

35 Scopus citations


Objective: Bipolar disorder (BD) is challenging to treat, and fewer treatments are available for depressive episodes compared to mania. Light therapy is an evidence-based nonpharmacological treatment for seasonal and nonseasonal major depression, but fewer studies have examined its efficacy for patients with BD. Hence, we reviewed the evidence for adjunctive light therapy as a treatment for bipolar depression. Methods: We conducted a systematic review of databases from inception to June 30, 2019, for randomized, double-blind, placebo-controlled trials of light therapy in patients with BD (CRD42019128996). The primary outcome was change in clinician-rated depressive symptom score; secondary outcomes included clinical response, remission, acceptability, and treatment-emergent mood switches. We quantitatively pooled outcomes using meta-analysis with random-effects models. Results: We identified seven trials representing 259 patients with BD. Light therapy was associated with a significant improvement in Hamilton Depression Rating Scale score (standardized mean difference = 0.43, 95% confidence interval [CI], 0.04 to 0.82, P = 0.03). There was also a significant difference in favor of light therapy for clinical response (odds ratio [OR] = 2.32; 95% CI, 1.12 to 4.81; P = 0.024) but not for remission. There was no difference in affective switches between active light and control conditions (OR = 1.30; 95% CI, 0.38 to 4.44; P = 0.67). Study limitations included different light treatment parameters, small sample sizes, short treatment durations, and variable quality across trials. Conclusion: There is positive but nonconclusive evidence that adjunctive light therapy reduces symptoms of bipolar depression and increases clinical response. Light therapy is well tolerated with no increased risk of affective switch.

Original languageEnglish (US)
Pages (from-to)290-300
Number of pages11
JournalCanadian Journal of Psychiatry
Issue number5
StatePublished - May 1 2020


  • bipolar disorder
  • depression
  • light therapy
  • meta-analysis
  • randomized clinical trials
  • systematic review

ASJC Scopus subject areas

  • Psychiatry and Mental health


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