Meta-Analysis Finds Antidepressants More Effective Than Placebo
Bipolar Network News
July 3, 2018

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.

Editor's Note: This meta-analysis should end any remaining controversy about the efficacy of antidepressants in the acute treatment of unipolar depression.

This study did not address maintenance treatment for the prevention of depressive episodes. Researcher John R. Geddes and colleagues have found robust, statistically significant data that continuation treatment with antidepressants can prevent depressive relapse, suggesting that if patients continue taking effective antidepressants, rather than switching to placebo, the antidepressants can reduce depressive occurrences by about 70%.

It is now recommended in most guidelines that patients with two or three prior episodes of depression consider staying on antidepressants indefinitely over their lifetime in order to prevent recurrence. Antidepressants increase the creation of new neurons and brain-derived neurotrophic factor (BDNF), which protects neurons and is important for learning and memory. Antidepressants can also prevent loss of hippocampal volume.