Common Antidepressant More Effective for Treating Anxiety

A common antidepressant might be more effective treating anxiety symptoms than it is at treating depressive symptoms.

A team from the University College London, led by Gemma Lewis, PhD, recently conducted the largest ever placebo-controlled clinical trial of an antidepressant and found sertraline (Zoloft), a selective serotonin reuptake inhibitor (SSRI), leads to an early reduction in anxiety symptoms commonly found in depression, long before any of the depressive symptoms are reduced.

In the trial, half of the participants were given sertraline daily for 12 weeks, while the remaining participants were given a placebo for the duration of the study.

The trial included 653 patients from 179 primary care surgeries in the UK with depressive symptoms of any severity or duration in the past 2 years.

The team found that the drug did not improve depressive symptoms, including low mood, the loss of pleasure, and poor concentration, within 6 weeks. They also found weak evidence that sertraline reduced depressive symptoms after 12 weeks.

However, the patients who took sertraline were twice as likely to self-report improvements in mental health than the placebo-controlled group.

“The mean 6-week [Patient Health Questionnaire, 9-item version] PHQ-9 score was 7.98 in the sertraline group and 8.76 in the placebo group (95% CI, .85—1.07; P =.41),” the authors wrote. “However, for secondary outcomes, we found evidence that sertraline led to reduced anxiety symptoms, better mental [but not physical] health-related quality of life, and self-reported improvements in mental health.”

The investigators also discovered that treatment response for either anxiety or depressive symptoms varied according to the severity of the actual symptoms.

The findings also support the continued prescription of sertraline and other similar antidepressants for patients with 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,” Lewis said in a statement. "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 investigators also reported 7 adverse events—4 in the sertraline group and 3 in the placebo group.

Sertraline has a similar pharmacological profile to other SSRIs and acts via a similar mechanism and the investigators expect the results to apply to other SSRIs when used in a similar patient population.

However, they cautioned that the findings might not translate to antidepressants of other classes.

Depression is generally managed in primary care, with most antidepressant trials featuring patients from secondary care mental health services, with eligibility criteria based on diagnosis and severity of depressive symptoms.

Depression is predicted to be the leading cause of disability in high-income countries by 2030.

The study, “The clinical effectiveness of sertraline in primary care and the role of depression severity and duration (PANDA): a pragmatic, double-blind, placebo-controlled randomised trial,” was published online in The Lancet Psychiatry.