The study, published in the Annals of Internal Medicine, included about 274 depressed adults (average age: mid-40s) who had been depressed for nearly 17 years.
The researchers split the patients into two groups. One group took Risperdal for six weeks. The other group took a pill containing no medicine (placebo). All patients continued their regular antidepressant medication.
Six weeks later, depression was in remission for about 24.5% of the Risperdal patients, compared with almost 11% of those taking the placebo.
Patients taking Risperdal were also more likely than those taking the placebo to have their depression symptoms ease to a lesser extent.
The most commonly reported adverse events were:
- Headache (nearly 9% of Risperdal patients and about 14% of those taking the placebo)
- Sleepiness (5% of the Risperdal patients and almost 2% of those taking the placebo)
- Dry mouth (5% of the Risperdal patients and nearly 1% of those taking the placebo)
The study also included a six-month follow-up to see if Risperdal helped prevent depression relapse.
Risperdal isn't approved by the FDA for depression treatment. It's approved for treating three conditions:
- Schizophrenia in adults and adolescents aged 13-17
- Short-term treatment of manic or mixed episode of bipolar disorder for people who are at least 10 years old
- Irritability in autistic children and teens aged 5-16
With regard to Risperdal, "the benefit of continuing longer-term treatment for patients who achieve remission is uncertain but may be limited to those with the least response to their initial antidepressant treatment," write the researchers.
The study was funded, designed, and supervised by Janssen Pharmaceutica, which makes Risperdal. The researchers, who included Ramy Mahmoud, MD, MPH, work for Ortho-McNeil Janssen Scientific Affairs. Ortho-McNeil and Janssen are both subsidiaries of Johnson & Johnson.