Compulsive shopping, gambling and cleaning associated with Parkinson's disease is actually caused by the drugs used to treat the disease, researchers have found.
Parkinson's disease, the neurodegenerative condition that can cause shakes and tremors, has been linked with alterations in behaviour in patients ranging from compulsive shopping and gambling to being obsessed with taking technical equipment apart, sorting objects or for taking long aimless walks.
Researchers have found that these side effects are caused by the drugs used to treat Parkinson's rather than the disease itself.
In a small study, a group of newly diagnosed Parkinson sufferers who were not taking any medication, were asked about their compulsive behaviour and the results compared to a similar group of people who were healthy.
It was found that one in five of both groups showed compulsive behaviour.
The findings from University of Pennsylvania were published in the journal Neurology.
"We've known for some time that these behaviours are more common in people taking certain Parkinson's medications, but we haven't known if the disease itself leads to an increased risk of these behaviours," said study author Dr Daniel Weintraub.
"These results provide further evidence that impulse control disorders that occur in people with Parkinson's disease are related to the exposure to the dopamine-related drugs, not just the disease itself," he said.
"More long-term studies are needed to determine if the 20 per cent of people who have some symptoms of these disorders are more likely to develop impulse control disorders once they start treatment for Parkinson's."
The symptoms can be controlled by altering doses of medication but drugs should not be changed or stopped without help from medical professionals.
Experts have said the behaviours are particularly associated with drugs known as dopamine agonists, but can also affect people who take other Parkinson's drugs, in particular levodopa.
Parkinson's symptoms are caused by a decrease in the levels of the chemical in the brain, dopamine, due to the death of the nerve cells in the brain that make it.
Dopamine agonists act in a similar way to natural dopamine in the brain and are particularly effective against the movement symptoms of Parkinson's.
