Prolonged use of antidepressants offers limited benefits while posing health risks, according to a new study that calls for clinicians to review treatments every six months.
A significant population of the more than 330 million people who suffer from depression globally take antidepressants daily, with nearly twice as many women taking them as men.
The majority of the people who take antidepressants in high-income countries, including the US, UK, and Australia, do so over the long term.
But a growing body of research indicates that commonly prescribed antidepressants do not work by rectifying any underlying deficiency of the brain hormone serotonin.
Researchers also warn that long-term antidepressant use can lead to much more severe withdrawal symptoms.
More worryingly, the new study reveals that the health benefits of long-term antidepressant use may be overstated.
“Much of the evidence supporting long-term antidepressant treatment comes from so-called relapse prevention trials,” Mark Horowitz, author of the study published in the Australian Journal of General Practice, said.
“These studies typically compare patients who continue medication with those who stop abruptly or rapidly,” Dr Horowitz, a psychiatrist at Adelaide University, explained. “Because they don’t distinguish between withdrawal symptoms and the return of depression, we believe many apparent relapses may actually be withdrawal effects.”
Researchers note that even short-term trials show antidepressants enabling only small improvements compared to placebos.
There is also growing evidence of risks associated with long-term antidepressant use such as sexual dysfunction, emotional numbing, cognitive impairment, and weight gain, scientists warn.
Stopping antidepressants after long-term use may also result in severe and long-lasting withdrawal symptoms, which can sometimes persist for months or even years.
“Symptoms such as anxiety, low mood and insomnia occur in both withdrawal from antidepressants and a return of depression,” Dr Horowitz said.
“As these studies do not distinguish between them, they will miscategorise withdrawal as a return of depression, as this is the focus of such studies.”
Scientists call for updating current clinical guidelines to reflect that there are no good studies showing the effectiveness of taking antidepressants in the long term.
“Concerningly, the risk of withdrawal effects appears to increase with the duration of use – one reason for stopping antidepressants sooner rather than later,” Dr Horowitz said.
“There is increasing emphasis on supporting patients to make informed choices about antidepressant use and to stop antidepressants by slowly decreasing the dose,” said Katharine Wallis, another author of the study from the University of Queensland Medical School.