This amazing study from 2012 proves bright light therapy to be effective in depression. But that’s not all! The study is lovable and distinguishable in two ways:

  • First, it investigates the effect of bright light therapy in patients taking antidepressants. This is important because we need to know how bright lamps work in conjunction with other treatments.
  • Second, it does not compare the bright light therapy to fake treatment or no treatment at all. Instead, it compares the effects of the light to known effects of physical exercise. This is very important because we already know that there is some effect of the light – we still need to explore whether the effect is better or worse than other procedures known to provide relief from depression.

During the course of the study, all psychiatric patients with major depression were treated with Duloxetine, an SNRI type antidepressant which is thought to increase baseline levels of serotonin and noradrenaline in the brain. Besides taking the pills, half of the participants were following a schedule of daily physical exercise known to alleviate depression. The other half of the participant group received chronotherapeutic intervention based on what we know about depression and the sleep-wake cycle: this treatment included temporal sleep deprivation, stabilization of sleep pattern, and bright light therapy.

Since we know that sleep deprivation temporarily alleviates depression, it was no surprise that during the first week of therapy, patients who were woken up extremely early improved much more than those in the exercise group. However, in the following 7 weeks, they were no longer kept awake: instead, they followed a regular sleep routine and received daily morning shine from a bright light lamp. This had a great effect: depression improved notably in 71% of the bright light patients compared to 47% of those who simply exercised. Further, 46% of patients receiving bright light therapy were no longer clinically depressed at the conclusion of the eight week study compared to only 23.1% of those exercising.

In other words: the light therapy made pharmacological treatment nearly twice as successful!

There is not much to criticize here. The researchers were blind to how individual patients were treated and as such, their evaluation could not be biased. Also, the patient group consisted of everyday depressed people arriving to various psychiatric clinics rather than a selected sample from laboratory experiments. However, regardless of how unbiased and seemingly accurate the study is, no conclusion can be made based on a single experiment. This is because the effect can be overestimated or only valid for a subgroup of depressed people. Together with other studies, it has the potential to prove that bright light lamps can treat depression. Still, much remains to be learned.

In two other articles devoted to depression, we gathered the evidence that phototherapy really works for depression, alone as well as with psychotherapy or antidepressants (you can check them here, here and here). There is, however, plenty of various devices to choose from. And meta-analyses that summarize data across different studies cannot help us with picking up the right one. So let’s just skip years of confirmatory studies for now and move to a clinical trial that achieved better than expected results using one particular type of therapy lamp: the Canadian study from 2016.

Bright light better than antidepressants, Canadian scientists found

The researchers split 122 patients into four groups: a quarter of them was receiving light therapy only, another quarter Prozac, the most famous antidepressant (SSRI-type) – and the rest either both of the treatments, or none of them. Plus, to keep placebo effect equal, the patients did not know which group they belonged to, because everyone was exposed to some device and everyone got some pill, whether it was Prozac or placebo.

Those receiving both, light therapy and Prozac, were doing best, followed by those exposed to bright light but not getting the antidepressants. Finally, the group receiving Prozac was doing slightly better than the one with no real treatment in average, but the difference was too small to be statistically relevant.

According to this single study, daily exposure to the Carex Light Therapy Lamp “for 30 minutes as soon as possible after awakening, preferably between 7 and 8 AM” was working better than 20 mg of Prozac.

I would not necessarily rely on this single research, though. Seeing many other studies on antidepressants, light therapy and psychotherapy, I would personally expect the benefits of light therapy to be slightly lower than those of more traditional approaches, pharmacotherapy or psychotherapy. In line with the authors of the research who concentrate on light therapy itself, rather than on comparison with pills:

“Light treatment, whether in monotherapy or particularly in combination with fluoxetine, is efficacious and well tolerated in the treatment of nonseasonal major depressive disorder”

Raymond W. Lam, MD; Anthony J. Levitt, MBBS; Robert D. Levitan, MD, MSc; Erin E. Michalak, PhD; Amy H. Cheung, MD; Rachel Morehouse, MD; Rajamannar Ramasubbu, MD; Lakshmi N. Yatham, MBBS, MBA; Edwin M. Tam, MDCM (2016). Efficacy of Bright Light Treatment, Fluoxetine, and the Combination in Patients With Nonseasonal Major Depressive Disorder A Randomized Clinical Trial. JAMA Psychiatry. 2016;73(1):56-63. doi:10.1001/jamapsychiatry.2015.2235.

In either case, we have yet another study proving light therapy efficient in depression. And how about choosing a particular light device? Personally, I would opt for the one from the study: Carex Day-Light Classic Plus Bright Light Therapy Lamp – 10,000 LUX At 12 Inches – LED Sun Lamp Mood Light.