Key messages

• We do not know if medicinal and non-medicinal treatments help reduce impulsive-compulsive behaviors in people with Parkinson's disease because the currently available evidence is limited and uncertain.

• We need more studies, with more participants, that explore the range of behaviors they develop, to reach conclusions about the best treatment options.

What are impulsive-compulsive behaviors (ICBs)?

Some people with Parkinson’s disease develop impulsive-compulsive behaviors (ICBs): behaviors that are hard to control and may happen repeatedly, even when they cause problems. Examples of ICBs include:

• gambling too much;

• spending or shopping uncontrollably;

• overeating or binge-eating;

• hypersexuality (increased sexual thoughts or behaviors);

• other repetitive, excessive, uncommon behaviors, such as sorting or taking things apart.

How are ICBs treated?

There isn’t enough clear evidence about the best way to treat ICBs in people with Parkinson’s disease. Some medications used to treat Parkinson’s can make ICBs worse, so doctors often reduce the dose— but this can lead to a return or worsening of the movement problems that people with Parkinson's disease develop.

Treatments that might help with ICBs in people with Parkinson’s disease include both medicinal and non-medicinal options. Medications may help by balancing dopamine levels in different parts of the brain. Dopamine is sometimes called the 'feel-good' chemical because it’s involved in the brain’s reward system. Non-medicinal treatments, including cognitive behavioral therapy (CBT) and non-invasive brain stimulation, aim to improve self-control and decision-making by strengthening the brain’s ability to manage impulses.

What did we want to find out?

We wanted to know if there are medicines or non-medicinal treatments (including lifestyle changes, exercise, counseling or behavioral interventions) that reduce the frequency and severity of ICBs, improve people's quality of life and other symptoms associated with ICBs in people with Parkinson’s disease.

What did we do?

We searched for studies that compared any of the active treatments described above (medicinal or non-medicinal approaches) to either a placebo treatment (i.e. an inactive or 'dummy' medicine) or no treatment in people with Parkinson's disease.

We compared and summarized the study results, and rated our confidence in the evidence, based on factors such as study methods and sizes.

What did we find?

We found four studies with a total of 151 participants. The average age of people in the studies ranged from about 58 to 61 years. Between 24% and 32% of the participants were women. Three studies tested three different medicines – amantadine, naltrexone and clonidine – and compared these to placebo treatment. One study explored cognitive behavioral therapy (CBT).

Because the studies tested different treatments and involved only small numbers of participants, we couldn’t combine the results to get more reliable conclusions.

Main results

Amantadine versus placebo

• The one study looking at this comparison did not measure most of the outcomes we were interested in.
• It did assess whether treatment led to any unwanted, harmful events compared to placebo. The evidence was very uncertain about whether there was any difference between the two groups.

Naltrexone versus placebo

• Compared to placebo, naltrexone may make little to no difference in the severity of ICBs.
• The evidence was very uncertain about the effect of naltrexone on unwanted, harmful events.

Clonidine versus placebo

• The evidence was very uncertain about the effect of clonidine on all the outcomes we were interested in, including: the frequency and severity of ICBs; unwanted, harmful events; and any changes in people's quality of life, depression and anxiety.

Cognitive behavioral therapy (CBT) versus no treatment

• CBT may make little to no difference in the frequency and severity of ICBs.

What are the limitations of the evidence?

We are not confident in most of the evidence because there were only a few studies with small numbers of participants. Not all the studies provided information about everything that we were interested in.

How current is this evidence?

We included evidence published up to 13 June 2025.