Parkinson's sufferers claim that their drugs have led them addicted to sex, shopping, twitter, gambling.
A woman who suffers from Parkinson's disease said her medication has left her craving sex, shopping and social networking.
Vicki Dillon, 40, from Hexham, Northumberland, was diagnosed with the incurable illness four years ago and has been taking prescribed drugs to keep the symptoms at bay.
But they have led to bizarre side effects, including an increased libido and spending thousands of pounds on clothes, partying and luxury holidays.
"The drugs heighten the pleasure-seeking parts of your brain," the Daily Mail quoted Vicki as saying.
"I always did enjoy shopping, but now I want to go out every weekend and buy new clothes all of the time. But most of the money I spend is on the family.
Mark Robson, 56, became obsessed with gambling after taking the dopamine agonist drug to control the symptoms of Parkinson's.
He ended up bankrupt and his wife divorced him.
Other studies found patients becoming addicted to sex, shopping or food.
Director of research and development at the Parkinson's Disease Society Dr Kieran Breen said: "Studies on the brains of Parkinson's sufferers show they are depleted in the chemical dopamine, which is responsible for movement.
"Drugs that replace the dopamine, or mimic it, have been found to help sufferers retain more mobility.
"The problem is that while dopamine agonist drugs are very good at helping Parkinson's sufferers retain movement, dopamine is also responsible for behaviour and, in some patients, one recognised side effect is compulsive addictive behaviour," he explained.