Some of the most popular anti-depressants, like Prozac and Seroxat, work no better than dummy pills on the majority of depressed people, new research suggests.
By Helen Neill
Newsbeat health reporter
Prozac is a well-known brand of anti-depressant
Scientists looked at the results from 43 clinical trials and found they helped only those suffering from the most severe depression.
The drugs are prescribed to millions of people in the UK every year.
Professor Irving Kirsch from the University of Hull, who led the study, said: "This means that depressed people can improve without chemical treatments."
The makers of Prozac and Seroxat, two of the commonest anti-depressants, said they disagreed with the findings, and that the drugs are effective.
Newsbeat listeners have been texting in with their experiences.
Rich from High Wycombe, in Buckinghamshire, said: "I took anti depressants but after a while became aware that they were not actually doing anything. I also know they take a long time to get into your body."
An anonymous sender, who suffered from postnatal depression, claimed Prozac saved her and her family from a "life of misery".
Drew from Leicester said Prozac and other similar drugs should only be prescribed as a "last resort".
"I spent four months on Prozac and without it, I dread to think how things would have turned out," he added.
Michael from Kent had a different take on the news.
"This study should not of been announced," he said. "Sufferers like me, who believed they were getting slightly better through taking anti-depressants, have now lost faith."
People who are on anti-depressants and are concerned about the study's findings are advised not to stop taking their medication without consulting a doctor first.
There can be side effects if patients come off them suddenly.