An estimated 7.8 million people in England, the equivalent of one in six adults, were issued at least one prescription of anti-depressants in 2019-2020. The number of prescriptions were 50 per cent higher in women.
The review, published in the Drug and Therapeutics Bulletin, found that most of the evidence for the effectiveness of antidepressants was based on placebo-controlled trials lasting between just six and 12 weeks.
Researchers, from University College London and Royal Cornwall Hospitals NHS Trust, said the results from the placebo group and those who took the medication did not meet the threshold for a “clinically important difference”.
However, side effects among those who were given selective serotonin reuptake inhibitors (SSRI), a modern type of anti-depressant, were common. One in five patients reported daytime sleepiness, dry mouth, profuse sweating and weight gain.
One in 10 said they felt restless or nauseous, had muscle spasms, constipation, diarrhea and dizziness. Additionally, a quarter of those on medication reported sexual difficulties.
“In light of this uncertain balance of benefits and harms, we should re-visit the widespread – and growing – prescription of antidepressants,” researchers said.
Another issue with existing evidence, highlighted by experts, is that it does not measure the effectiveness of anti-depressants on outcomes that matter most to patients.
Studies primarily focused on measuring the symptoms of depression, rather than examining the social functioning or quality of life of patients.
Additionally, researchers found that those who stay on antidepressants for extended periods of time often experience withdrawal symptoms such as anxiety, insomnia, agitation, appetite changes and depression when coming off the medication.
Gradual dose tapering may best help patients to stop, although “there is no guarantee that patients will avoid consequences such as long-lasting sexual side effects or persistent withdrawal symptoms even with a cautious taper,” researchers said.
They noted that long-term users of antidepressants may need help coming off them, but “there are currently no dedicated NHS services to support antidepressant de-prescribing”.
In 2018, an international study led by researchers at the University of Oxford and Japan’s Kyoto University studied anti-depressant trial data involving more than 116,000 participants.
They found that “all anti-depressants were more efficacious than placebos in adults with major depressive disorder”.
Andrea Cipriani, a lead author of the study, said the findings show that anti-depressants are an “effective tool for depression”.
“Untreated depression is a huge problem because of the burden to society,” he told The Guardian.