Spotlight on impulse control behaviours and disorders in people with Parkinson’s

While they are more common in people taking dopamine agonists, they can also occur in all people taking other dopaminergic therapies like levodopa. These behaviours can include pathological gambling, hypersexuality, compulsive shopping, and binge eating. They are understood to stem from the medication dysregulating the brain's reward system. News stories have focused on people who experienced severe consequences as a result of these drug side effects, including financial ruin, damaged relationships, loss of employment, and an increased burden on caregivers. 

Many people with Parkinson’s report that they weren't warned about the risk of developing impulse control behaviours when they were prescribed these drugs. This is despite the Medicines and Healthcare products Regulatory Agency (MHRA) issuing advice stating that all people on dopaminergic therapies should be warned about these side effects since 2007. Statement 2 of the NICE Parkinson's Disease quality standard also states that adults with Parkinson's taking dopaminergic therapy are given information about the risk of impulse control disorders, when starting treatment and at least annually after that. 

Our research has demonstrated that this message isn't reaching some patients. Our 2025 Audit showed that 1 in 4 people with Parkinson's on dopaminergic therapy did not have a recorded discussion about impulsive behaviours in the preceding year. Read the 2025 Audit reports here.

BBC investigation

The BBC’s recent year-long investigation into the issue raised questions about the accuracy of the warnings provided by pharmaceutical companies in drug leaflets. It challenged the claim made in these leaflets that these side-effects are 'rare', which inaccurately suggests they occur in fewer than 1 in 100 patients. The MHRA has now confirmed it will be updating that label to 'common'. 

In response to this investigation, the MHRA also announced that it would be reviewing warnings for 8 dopamine agonist drugs. Layla Moran MP, who heads the Health Select Committee told the BBC she believes the MHRA should apologise to patients. Read the full BBC article.

Dr Alison Cave, MHRA chief safety officer, told SkyNews the regulator would determine if it needed to take regulatory action to increase awareness of the risk. 

"Patient safety is our top priority [...] No medicine is risk-free and impulse control disorders are a known risk for patients prescribed dopamine agonists. Our sympathies are with those affected by any side effects from their use," she said. Go to the SkyNews article.

Reporting side-effects and further information

The MHRA is encouraging patients and healthcare professionals who suspect side effects with these medicines to alert its Yellow Card scheme, which collates adverse experiences of drugs.

As a health professional working in Parkinson's care, you'll find useful information in our guide: Understanding impulse control behaviours and disorders in Parkinson's: A guide for health professionals. 

We also encourage you to direct people with Parkinson's and their families to our patient-facing information: Impulsive and compulsive behaviours in Parkinson's.