Light therapy: It's long been a go-to therapy for seasonal affective disorder (SAD), a kind of depression that can beset some people when winter looms and days shorten.

But new research is suggesting that time spent in front of light box might ease other forms of depression as well.

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The new review of data was led by Artur Menegaz de Almeida, of the Federal University of Mato Grosso in Sinop, Brazil. His team noted that, right now, light therapy's effectiveness has only been proven against SAD.

However, “Bright light therapy has been studied as a potential adjunctive treatment for major depressive disorder, as light exposure is well understood to affect human mood and cognitive function,” he said in a news release from the American Psychiatric Association.

Reporting Oct. 2 in the journal JAMA Psychiatry, the Brazilian team pored through data from 11 randomized clinical trials involving a total of 858 patients. These people had diagnoses of nonseasonal forms of major depression or bipolar depression.

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Some patients used light therapy in addition to whatever medication they had been prescribed. Therapy was defined as sitting in front of fluorescent 10,000 lux-powered light box for at least 30 minutes, with treatment lasting for between 1 and 6 weeks.

Their outcomes were compared to those of patients on other adjunct treatments, such as air ionizers or dim red light.

A 50% or more reduction in depressive symptoms was deemed to be a good response to treatment.

According to the researchers, 60.4% of those engaged with the light therapy achieved that goal, compared to 38.6% of those getting the other add-on treatments.

Full remission from depression was also markedly higher among the light therapy group vs. those who didn't get the therapy: 40.7% versus 23.5%, respectively.

These success stories occurred relatively quickly, with a good response or remission typically happening within a month.

Light boxes are much cheaper than many drugs or psychotherapy sessions, the research team noted.

“The primary supportive argument in favor of using bright light as an adjunctive treatment is the cost,” they wrote. “Even though outpatient treatment costs with antidepressants are widely variable, exposure to external light generally involves no costs or limitations, which reinforces the need to firm [bright light therapy] as an efficient adjunctive treatment for nonseasonal depressive disorders.”