Drug for Parkinson Disease may be Linked to Disordered Gambling

Parkinson disease is often treated with dopamine agonists such as apomorphine. Dopamine agonists may be the cause of other disorders reported to be prevalent among those with Parkinson disease. Individuals with Parkinson Disease have been reported to have a high rate of disordered gambling and other impulse control disorders.

A new study looks at the relationship between dopamine agonists and impulse control disorders (Weintraub et al., 2010). Besides disordered gambling, other impulse control disorders include compulsive shopping, binge-eating and hypersexuality. The study uses a large cross-sectional design to examine impulse control disorders among those with Parkinson disease.

The researchers recruited 3,090 participants from patients at 46 movement disorder centers in the U.S. and Canada. The participants were included in the study if they met certain criteria. Patients must be between 30 and 75 years; a history of taking medication for Parkinson Disease for at least one year and showing a response to treatment; had not stopped or started therapy in the last six months.

The participants were each assessed for several impulse control disorders using interviews and formal diagnostic tools, including the Massachusetts Gambling Screen, the Minnesota Impulse Disorders Interview, and the DSM-IV.

The researchers used odds rations to determine the impulse control disorder frequencies between Parkinson disease patients on dopamine agonist therapy and patients undergoing other types of treatment.

The results of the study showed that when compared to Parkinson disease patients not being treated with a dopamine agonist, those treated with a dopamine agonist were 2.7 times more likely to be diagnosed with an impulse control disorder, and 2.8 times more likely to be diagnosed with disordered gambling.

The results showed that overall, 17.1 percent of patients taking dopamine agonists were identified as having one or more impulse control disorders. This is in comparison with those on other types of treatment, at 6.9 percent having impulse control disorders. Binge eating disorder was highest among those not using a dopamine agonist at 5.6 percent.
Many of the patients showing an impulse control disorder were diagnosed with more than one. The average number of impulse control disorders among the patients treated with a dopamine agonist was 1.38.

The study’s results may be limited by the use of a cross-sectional design because side effects of treatments for Parkinson disease may change over time.

The findings of the study show the significant risk for impulse control disorder found among Parkinson disease patients who are treated with dopamine agonists. Healthcare providers have an opportunity when prescribing treatment to talk with the patient and the patient’s family about the significant risk for developing an impulse control disorder.