Meta-Analysis Finds Antidepressants More Effective Than Placebo
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.
Psychiatric Medications Just as Effective as Medications for Other Illnesses
The popular media has sometimes scrutinized research on psychiatric medications, suggesting that they are not as effective as pharmaceutical companies would have us believe. Researchers in Germany recently performed a meta-analysis of research on psychiatric medications and found that the effect sizes for psychiatric drugs were comparable to effect sizes of other types of drugs. (Effect sizes communicate the size of the change that a drug brings about in patients.) The study was published in the British Journal of Psychiatry.
From the abstract:
Any comparison of different outcomes in different diseases can only serve the purpose of a qualitative perspective. The increment of improvement by drug over placebo must be viewed in the context of the disease’s seriousness, suffering induced, natural course, duration, outcomes, adverse events and societal values.
Antidepressants Work Better in Major Depressive Disorder than Previously Thought
As we’ve written before, the popular media has sometimes questioned the efficacy of antidepressants for unipolar depression. A reanalysis of data from previous controlled trials of fluoxetine and venlafaxine that was recently published in the Archives of General Psychiatry provides new evidence that these drugs are significantly more efficacious than placebo in youth, adult, and geriatric populations with major depressive disorder.
The researchers concluded,
To our knowledge, this is the first research synthesis in this area to use complete longitudinal person-level data from a large set of published and unpublished studies. The results do not support previous findings that antidepressants show little benefit except for severe depression. The antidepressants fluoxetine and venlafaxine are efficacious for major depressive disorder in all age groups, although more so in youths and adults compared with geriatric patients. Baseline severity was not significantly related to degree of treatment advantage over placebo.
