Some reviews of antidepressants for depression in adults find benefit[13] while others do not.[14] Evidence of benefit in children and adolescents is unclear. The twenty one most commonly prescribed antidepressant medications were found to be more effective than placebo for adults with major depressive disorder in a 2016 meta-study.[15] There is debate in the medical community about how much of the observed effects of antidepressants can be attributed to the placebo effect, with some claiming that there is no effect above and beyond it.[16][17] Most research on whether antidepressant drugs work is done on people with very severe symptoms,[18] a population who exhibits much weaker placebo responses,[19] so the results cannot be extrapolated to the general population.[20]