A small study suggests that a nutritional supplement sold over-the-counter may help some people with depression who haven't gotten better with any other drugs.
Researchers found that adding the supplement, called S-Adenosyl Methionine, or SAMe, to patients' antidepressant treatment helped more people with major depression improve their symptoms than those that took an inactive placebo on top of their normal medication.
The supplement also had fewer side effects than medications that are approved by the FDA for people with depression who don't respond to antidepressants.
"This is an exciting, yet preliminary, finding," Dr. George Papakostas, the study's lead author and a psychiatrist at Harvard Medical School and Massachusetts General Hospital, Boston, told Reuters Health.
At some point in their lives, up to 10 percent of people will suffer from major depressive disorder, defined as at least two consecutive weeks with multiple symptoms of depression, Papakostas said. About half of those people won't get better, even after trying a few different antidepressants, he said.
While there are a few medications approved by the FDA that these patients can take in addition to standard antidepressants, those drugs — called atypical antipsychotics — can have serious and sometimes life-threatening side effects, Papakostas said.
In the current study, which is published in the American Journal of Psychiatry, Papakostas and his colleagues gave SAMe to 39 people who had major depressive disorder that hadn't gotten better on antidepressant therapy. These people took 1,600 milligrams of SAMe each day in addition to the antidepressant treatment they were on before the study started. Another group of 34 similar patients took a placebo pill on top of their antidepressants. Neither group knew which treatment they had.
The authors then used two standard tests for depression to measure patients' symptoms each week for the next six weeks.
About a quarter of patients in the study dropped out because they weren't getting better or didn't feel well on SAMe or the placebo. But SAMe had no serious side effects, and a similar number of patients stopped the study because they didn't like SAMe and because they didn't like the placebo.
Among the 31 patients taking SAMe and the 24 taking placebo that completed the full six-week study, both depression tests showed that more patients on SAMe than on placebo responded to treatment and got better.
Previous studies have shown that SAMe can influence chemicals in the brain and might work as an antidepressant on its own or interact with traditional antidepressants, but the way it works isn't completely clear.
SAMe is found naturally in the human body and is sold as a supplement by vitamin stores. But it's more expensive than many current antidepressants, said Dr. Raymond Lam, the director of Mood & Anxiety Disorders at The University of British Columbia, who studies SAMe. The treatment will probably run more than $100 a month he said, and it's unclear whether it could be covered by insurance in the future.
The authors say that long-term studies will be needed to see if SAMe is as effective in helping patients with major depressive disorder as their results suggest.
The finding, Papakostas said, "is exciting because (SAMe) works differently than what we have now — it doesn't seem to be associated with the kind of side effects that FDA-approved treatments for this niche have." But, he said, "like other findings in medicine, it needs to be replicated."
Lam agreed. "We're always careful about these small studies," he told Reuters Health. "Depression is a complicated condition. We don't know exactly what works for which people, and so it is important that people don't rush out and stop taking whatever they're taking in order to use a new treatment."
The study was funded by the National Institute of Mental Health, and both SAMe and placebo pills were provided by the dietary supplement company Pharmavite, which markets SAMe.
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