Anxiety reduction with antidepressants confirmed, long-term effects uncertain

A new Cochrane review confirms that antidepressants effectively reduce symptoms of generalized anxiety disorder (GAD) under trial conditions, although there is limited data on long-term usage.

GAD affects millions of people worldwide and is characterized by excessive worry about everyday issues. Antidepressants, particularly selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), are recognized treatments for GAD, recommended by many national bodies including the UK's National Institute for Health and Care Excellence. However, misconceptions remain among some healthcare professionals and patients who do not realise that 'antidepressants' have wider uses beyond depression, while the term also carries stigma for many people.

The review analyzed 37 randomized controlled trials with over 12,000 participants, comparing antidepressants to a placebo. Most trials were primarily conducted in high-income countries, including the United States of America and various European countries, and recruited adults of both sexes. In most cases, there were slightly more female participants (~60%) which reflects the clinical prevalence of GAD.

Results showed that antidepressants were more effective than placebo in reducing anxiety symptoms, with a 41% higher response rate among those taking the medication compared to those taking a placebo. The review found no significant difference in dropout rates between those taking antidepressants and those taking a placebo, indicating that these medications are generally well-tolerated.

The research shows that antidepressants are highly effective at treating GAD, at least in the specific circumstances seen in trials. For people with Generalized Anxiety Disorder and no other conditions, we have good evidence that antidepressants lead to clinically meaningful improvements over a one- to three-month period compared to placebo.

We don't have enough evidence to say how effective they may be in patients with GAD alongside other mental health conditions, which is much more common in clinical practice. Most of the patients I see with GAD also have other mental health conditions, so future trials should investigate the effects of different treatment strategies on patients with multiple conditions."

Dr. Giuseppe Guaiana, Senior Author, Associate Professor of Psychiatry at the Schulich School of Medicine & Dentistry, Western University, and Chief of Psychiatry at St Thomas Elgin General Hospital

The review also highlights the lack of data on the long-term effects of antidepressants. Most included trials lasted between 4 to 12 weeks, with no long-term follow-up.

"We don't have enough information on the potential long-term benefits and harms of antidepressants, even though people often take them for years," says first author Katarina Kopcalic, who conducted the review at Western University. "This is an area that needs further exploration in future trials."

Despite these limitations, the review delivers a clear message: antidepressants are effective for managing GAD, particularly for patients who do not respond well to non-pharmacological treatments. However, more independent, long-term research is needed to understand their full impact, especially in patients with multiple conditions.