Light Therapy for Depression…

Antidepressants like Prozac and Paxil are widely used to treat depression, but a much less costly alternative called bright light therapy, in which a patient sits under an artificial light for a set period of time each day, is not. Light therapy is typically recommended for seasonal affective disorder, the “winter blues” brought on by shorter days and limited sun. Some psychiatrists prescribe it for this condition, often as a last resort when patients fail to respond to drugs.

One reason light therapy hasn’t been used in more people with depression is that there aren’t many good clinical trials of the therapy in depressed patients without seasonal affective disorder. There isn’t much money to be made from the treatment — all it involves is a one-time purchase of a special lamp. The upside is that it has few, if any, side effects (though, doctors note, it should always be done in consultation with a physician).

Now a new, carefully designed randomized controlled trial — of the kind considered the gold standard in medicine — suggests bright light therapy deserves a closer look.

The study was small, involving only 89 patients ages 60 and older, but the results were remarkable. Compared with a placebo, light therapy improved mood just as well as conventional antidepressant medications, said Dr. Ritsaert Lieverse, the paper’s lead author and a psychiatrist at the VU University Medical Center in Amsterdam.

“The effect sizes we found in this study are comparable to those reported for antidepressants, so I think efficacy is of comparable magnitude,” Dr. Lieverse said in an e-mail.

The report was published this week in The Archives of General Psychiatry.

Participants were evaluated at the beginning of the study using the Hamilton Scale for Depression, a questionnaire that doctors use to assess the severity of depression. They were then randomly assigned for three weeks to either bright light therapy or a dummy red light used as a placebo for comparison.

Since depression is often accompanied by poor sleep and other symptoms suggestive of circadian rhythm disruption, the scientists also examined markers of circadian function. The theory is that bright light therapy may act to elevate mood by activating the brain’s so-called circadian pacemaker, a structure called the suprachiasmatic nucleus. As part of the study, researchers assessed sleep quality and measured patients’ melatonin, a hormone critical for sleep-wake cycles, and urinary cortisol and salivary cortisol levels, measures of stress.

Dr. Lieverse said bright light therapy may also work by targeting depression-associated neurotransmitter systems that regulate serotonin and dopamine.

After three weeks of treatment, 43 percent of the patients who received bright light therapy had improved scores on the depression scale, compared with 36 percent of those who were assigned to the placebo treatment.

Treatment was then stopped, and patients were evaluated again three weeks later. Interestingly, those who had received the light therapy continued to improve, with 54 percent now having an improved score on the depression scale, while improvement declined in the placebo group, to 33 percent.

Those who got the active treatment were also sleeping better; their urinary and salivary cortisol levels dropped compared with the placebo group, and their melatonin levels increased steeply in the evenings in comparison to the placebo group.

Bright light therapy is already indicated for specific conditions like certain sleep disorders, jet lag, Alzheimer’s disease and postpartum depression, Dr. Lieverse said, but should be considered for major depression because of its benefits, especially the apparent lack of adverse side effects.

“Light therapy is now evolving as an effective depression treatment not only to be used in seasonal affective disorder,” he said.

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