New research shows that the anti-psychotic drug Risperdal may increase gynecomastia, also known as male breast growth, in older men. Risperdal is manufactured by Janssen Pharmaceuticals, and is often used to treat autism and bipolar disorder.

Over the past few years, there has been a growing interest in the risk of patients developing gynecomastia while taking Risperdal. While a lot of the attention has been focused on adolescent males developing breasts while taking Risperdal, the focus recently turned to the development of gyneocomastia in adult men.

In a recent study presented to the American Association for Geriatric Psychiatry, drug safety researchers found that patients using Risperdal were 69 percent more likely to suffer from male breast growth than non users. During the experiment, Mahyar Etminan, the lead author of the study, was particularly interested in learning whether Risperdal created a greater risk in developing gynecomastia than other antipsychotic drugs currently on the market. Based on Etminan’s results, Risperdal does.

The study was conducted by reviewing a health plan claims database. Claims of 1 million men between the ages of 45 and 80 were reviewed over a 10-year period. Out of those men, over 8,285 cases of gynecomastia were identified.

Dr. Iqbal Ahmed, a clinical professor of psychiatry and geriatric medicine at the University of Hawaii, told Medscape Medical News that he didn’t think the study revealed anything new, but confirmed what was previously suspected on a much larger scale.

Dr. Ahmed states that physicians should keep this information in mind before prescribing Risperdal to patients. He noted that while the increased risk of developing gynecomastia was certainly a disadvantage compared to other drugs, for some patients advantages in using Risperdal may still exist. He also pointed out the importance of physicians disclosing the potential side effects of drugs like Risperdal with patients.

 Although the exact link between gynecomastia, commonly referred to as “man boobs,” and Risperdal is unknown, scientists theorize the drug increases levels of prolactin. This is a hormone that stimulates breast growth in women.

Because of Risperdal’s effect on prolactin hormone levels, many men prescribed Risperdal may also begin to develop breast tissue, and/or experience nipple pain, nipple discharge (lactation) or painful breasts. For many men, young and old, this is an embarrassing condition that can cause physical and emotional pain, and in some cases requires surgery.

Hundreds of lawsuits have been filed against Janssen Pharmaceuticals and its parent corporation Johnson & Johnson. Most of the lawsuits are being filed on behalf of male plaintiffs between the ages of 10-18 who experienced adverse side effects from taking Risperdal. But with new studies linking Risperdal to an increased risk of gynecomastia in men of all ages, this age range may soon expand.

Johnson & Johnson has had to pay billions of dollars in fines and lawsuit settlements over Risperdal’s marketing strategies. The first private Risperdal settlement occurred in 2012. It was brought by a 21-year-old male who had to undergo breast removal surgery and allegedly suffered severe psychological trauma from the Risperdal side effects.