Health researchers say most patients who take antidepressants don't benefit directly from the active ingredients in the drugs and should consider lifestyle changes instead.
The researchers, led by Auckland family doctor and academic researcher Bruce Arroll, reviewed international studies on the use of antidepressants.
They found that both older and newer generation antidepressants work, but not for as many people as might be expected.
Professor Arroll says the drugs' ingredients provide active benefit only to about 10% to 15% of users. Overall, he says, 65% of those on antidepressants report feeling better as a result, but most of that can be attributed to a placebo effect.
Professor Arroll says those who feel depressed should consider doing exercise, altering thought patterns and keeping a "gratitude diary".
The review has just been published in the Cochrane Library of medical research studies.