A major scientific study—which involved nearly 120,000 people—claims to have settled the debate over how effective anti-depressants are by proving that they do actually work. The study, published by The Lancet on Thursday, claims to have proven that the 21 common anti-depressants used in the project were all more effective at treating acute depression than placebo pills. The scientists reached their findings by analyzing data from 522 trials including 116,477 people. However, the study did show different types of anti-depressant were more effective than others, with some just one-third more effective than placebos and others being more than twice as effective. The Royal College of Psychiatrists told the BBC that the study “finally puts to bed the controversy on anti-depressants.”