A vast study that sought to settle a long-standing debate about whether or not antidepressant drugs really work has found they are indeed effective in relieving acute depression in adults.

The international study — a meta-analysis pooling results of 522 trials covering 21 commonly used antidepressants and almost 120,000 patients — uncovered a range of outcomes, with some drugs proving more effective than others and some having fewer side effects.

But all 21 drugs — including both off-patent generic and newer, patented drugs — were more effective than placebos, or dummy pills, the results showed.