Letter
To the Editor: The article by Sit and colleagues (1), published in the February 2018 issue of the Journal, reports the high efficacy of antidepressant midday light treatment for bipolar disorder. Bipolar depression is a difficult-to-treat condition, with low success rates of antidepressant drugs (2). We thus welcome midday light treatment as a new treatment option. However, the study infers that antidepressant morning light treatment of bipolar depression can trigger mixed states (3) or is equal to placebo (4), so that its use is contraindicated.
We should not lose sight of a large body of evidence demonstrating that morning bright light treatment for bipolar depression is efficacious and safe. This has been highlighted in a meta-analysis (5) and in two recent randomized placebo-controlled trials (6, 7). Furthermore, a historical review (8) of 41 studies published between 1982 and 2017 administering light treatment to 799 patients with bipolar depression, mostly in the morning, showed that the rate of switch is lower than the 4% switch rate expected during placebo treatment of bipolar depression (9), thus not justifying specific concerns about manic switches after light treatment. Morning timing appears to have been forgotten, leading to an uncomfortable and unjustified either/or situation for midday or morning light treatment.
We wish to emphasize, in the absence of trials directly comparing midday and morning light treatment, that because of its proven efficacy and safety, early morning bright light treatment for bipolar depression, as many of us have used it in everyday clinical practice as an antidepressant adjunct to mood stabilizers, should be recognized as a valid treatment option.
DOI: 10.1176/appi.ajp.2018.18020231