Much of past evidence suggesting antidepressants are no more effective than placebo comes from the work of Irving Kirsch, associate director of the Program in Placebo Studies at Harvard Medical School.
In some cases, people are put on increased dosages because they believe their depression isn't getting any better.
Twenty-one commonly used antidepressant medications appeared more effective than placebo for the treatment of major depressive disorder in adults, according to findings from an worldwide study.
Professor Carmine Pariante, from the Royal College of Psychiatrists, said: "This meta-analysis finally puts to bed the controversy on antidepressants, clearly showing that these drugs do work in lifting mood and helping most people with depression". Some had small impacts, while others were moderate, depending on the drug. There are still significant voids in our understanding of depression, but this should ease the mind of both doctors administering and patients taking the antidepressants.
Of course, if one drug were always more effective than the others, then we wouldn't need so many antidepressants-doctors could simply prescribe the best one to all patients.
But the most effective drug at reducing depression was amitriptyline, a drug first discovered in the 1950s.
The researchers found that all antidepressants were more effective than placebo in terms of efficacy, with odds ratios ranging from 2.13 for amitriptyline to 1.37 for reboxetine.
Trump administration issues proposed rule to expand short-term insurance plans
That's in line with what President Donald Trump wanted when he signed an executive order on the issue in October. The plans are only cheaper because they skirt federal consumer protections .
To make things even more complicated, different people have different problems and experience different results, that's why we have more than one antidepressant in the first place. Something that may work for one person may have a completely different reaction for someone else.
However, Dr Cipriani added, "Antidepressants can be an effective tool to treat major depression, but this does not necessarily mean that antidepressants should always be the first line of treatment".
'Medication should always be cnsidered alongside other options, such as psychological therapies, where these are available'. Comparative efficacy and acceptability of 21 antidepressant drugs for the acute treatment of adults with major depressive disorder: a systematic review and network meta-analysis.
More than 300 million people worldwide have depression, according to the World Health Organization, of which less than half recieve effective treatments. The meta-analysis includes data on 116,477 patients total, from double-blind, randomized controlled trials published between 1979 and 2016.
"The large amount of data allowed more conclusive inferences and gave the opportunity also to explore potential biases". Two drugs (agomelatine and fluoxetine) appeared to be better tolerated than placebo, with less dropouts due to side effects, and only one drug (clomipramine) was more poorly tolerated than placebo.
"Importantly, the paper analyses unpublished data held by pharmaceutical companies, and shows that the funding of studies by these companies does not influence the result, thus confirming that the clinical usefulness of these drugs is not affected by pharma-sponsored spin", she said.