An analysis of 10 years of FDA data offers compelling evidence that common Parkinson’s drugs, which are also used to treat restless leg syndrome, can have nasty behavioral side effects.

A class of drugs called dopamine agonists, used mainly to treat Parkinson’s disease, has long been suspected of causing strange psychological side effects, such as compulsive gambling and sexual activity. But a meta-analysis published today in JAMA Internal Medicine aims to settle the question and change the way doctors, patients, and regulators handle the drugs.

The analysis of adverse events reported to the Food and Drug Administration over a 10-year period linked the drugs to excessive gambling and sexual behaviors, but also to shopping sprees, stealing, and binge eating. More incidents stemmed from the use of pramipexole and ropinirole than from other drugs in the class.

“As a paper it really isn’t telling us anything we didn’t know, it’s just reinforcing it. But it needs reinforcing because most physicians aren’t aware of the problem or underestimate the severity,” said Dr. Howard Weiss, an associate professor of neurology at Johns Hopkins University, who published a commentary that accompanies the study.

Dopamine receptor agonists were prescribed 2.1 million times in the last four months of 2012 alone. The drugs are a second-line treatment for Parkinson’s disease, after the dopamine replacement drugs levodopa and carbidopa. Dopamine agonists are also prescribed for other conditions, including restless leg syndrome and the hormonal condition hyperprolactinemia.

As many as 1 in 7 patients who take dopamine agonists experience psychological side effects, the analysis suggests.

“That is a striking psychological side effect rate,” said study author Thomas Moore, a drug safety researcher at the Institute for Safe Medication Practices. “There are a lot of forms of impulse control, but this is a striking and unusual list” of behaviors.

Find Out More About Restless Leg Syndrome »

Joshua Gagne, a pharmacoepidemiologist at Harvard Medical School who evaluated the statistics in a note that ran alongside Moore’s analysis, called the number of reported incidents “eyebrow raising.”

“It’s rare that we see such large measures of association,” he said.