According to researchers at University College London, this is the largest-ever placebo-controlled trial of an antidepressant that has not been funded by the pharmaceutical industry. Sertraline is one of the most commonly prescribed antidepressants.
The study included 653 people in England, between the ages of 18 and 74, with depressive symptoms of any severity or duration in the past two years. In all cases, there was clinical uncertainty about whether to prescribe an antidepressant, according to the researchers.
Just over half (54 percent) of the participants met a commonly used criteria for depression from the World Health Organization, while 46 percent met the criteria for generalized anxiety. That includes 30 percent who met the criteria for both conditions, 15 percent who had mixed anxiety and depressive disorder, and 15 percent who did not meet diagnostic criteria, but still had symptoms, the researchers reported.
Half of the participants were given sertraline for 12 weeks, while the other half were randomly assigned to the control group and given placebo pills for 12 weeks.
The researchers found no evidence of a clinically meaningful reduction in depressive symptoms after six weeks.
However, there was strong evidence that sertraline reduced generalized anxiety symptoms, with continued improvement from six weeks to 12 weeks, leading to a better mental health-related quality of life.
According to the researchers, participants who took sertraline were twice as likely as those who took a placebo to say their mental health had improved overall. This is an important measure of improvement, from the patient’s perspective, and can be used to gauge clinically meaningful treatment effects, researchers said.
The results did not vary by severity or duration of the depressive symptoms, suggesting that antidepressants may benefit a wider group of people than previously believed, including people who do not meet diagnostic criteria for depression or generalized anxiety disorder, researchers added.
The researchers say their findings support the continued prescription of sertraline and other similar antidepressants for people experiencing depressive symptoms.
“It appears that people taking the drug are feeling less anxious, so they feel better overall, even if their depressive symptoms were less affected,” said lead author Dr. Gemma Lewis. “We hope that we have cast new light on how antidepressants work, as they may be primarily affecting anxiety symptoms, such as nervousness, worry and tension, and taking longer to affect depressive symptoms.”
The study was published in The Lancet Psychiatry.
Source: University College London