"In a 2018 article in the journal The Lancet, researchers led by Andrea Cipriani compared the efficacy of 21 different antidepressants and established that antidepressants are more effective than placebo at reducing unipolar depression. To date, this is the largest meta-analysis of double-blind, randomized controlled studies of antidepressant efficacy, including 522 trials and a total of 116,477 participants. All 21 of the antidepressants were found to be more effective than placebo.Looking at head to head studies, Cipriani and colleagues found that the most effective antidepressants were agomelatine, amitriptyline, escitalopram, mirtazapine, paroxetine, venlafaxine, and vortioxetine. The least effective antidepressants were fluoxetine, fluvoxamine, reboxetine, and trazodone.In terms of tolerability, agomelatine, citalopram, escitalopram, fluoxetine, sertraline, and vortioxetine were most tolerable to patients, while amitriptyline, clomipramine, duloxetine, fluvoxamine, reboxetine, trazodone, and venlafaxine caused the most study dropouts due to side effects. Only agomelatine and fluoxetine had better dropout rates than placebo.Interestingly, agomelatine, the medication found to be most effective and most tolerable, is unavailable in the US. Pharmaceutical company Novartis, which owns the rights to the drug, was disappointed by some lackluster studies of the drug and never applied for Food and Drug Administration approval to sell it in the US. The studies found potential problems regarding drug interactions related to the metabolic enzyme CYP1A2 and a risk of liver damage with longer-term use.