Evidence gathered across available literature shows that bright light therapy helps people simultaneously treated with antidepressants.

“Ten studies involving 458 patients showed improvement using bright light therapy augmentation versus antidepressant pharmacotherapy alone. The effect size was similar to that of other accepted augmentation strategies, roughly 0.5.”

Penders TM, Stanciu, CN , Schoemann AM, Ninan PT, Bloch R, Saeed SA (2016). Bright Light Therapy as Augmentation of Pharmacotherapy for Treatment of Depression: A Systematic Review and Meta-Analysis. The primary care companion for CNS disorders.

There is “evidence for the efficacy of use of bright light therapy” in addition to pharmacological treatment for major depression and bipolar disorder.

Stunning, miraculous, great results! The effect size of 0.5 would normally be considered medium, but in this case, it is unexpectedly high. The reason is simple: when two treatments are applied together, they always appear to be much less effective than they actually are. This is because when another remedy is applied simultaneously, it takes part of the job away from the first treatment so the effects are reduced, as we explain in this article). Therefore, this study presents a strong argument in favour of phototherapy.

Studies like this, so called meta-analyses, have great scientific power. The researchers gather all published data that comply with some criteria, evaluate them according to their quality, like number of participants and the methodology behind, and finally calculate the total result and their weighted average. The final number is quite trustworthy, because it contains all answers we have to the question we ask, so it overcomes possible coincidences or errors in single studies.

As an advice for clinical practice, they have, however, one drawback: as they compile existing results rather than collecting their own data, they often do not offer us exact guidance. This one, for example, gathered results of studies that were using bright light lamp of at least 5000 lux for at least 30 minutes daily.

But which light therapy device to use and how?

For guidelines about intensity of the light and time of exposure, we can simply rely on the well-established protocol for depression, advising exposure to light of 10.000 lux for 30 minutes every morning, preferably immediately after awaking.

When choosing a particular device, it might be recommendable to check some single studies with great results, and see which lamps they have used. With respect to depression and antidepressants especially, we have a double-blind, controlled clinical trial from a group of Canadian scientists, who had better results than I would ever expected: according to their study, light therapy was distinctively more powerful than antidepressants. And because they had used the Carex Day-Light Classic Plus Bright Light Therapy Lamp, I highly recommend following their example!