Compulsive gambling associated to Parkinson’s drug treatment |
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Published
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Wed, 13 Jul 2005 01:05
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A recent case study links the “dopamine agonist” drugs used to treat Parkinson’s syndrome to a condition of pathological gambling. The study was startling not only for the link between onset of compulsive behaviors and the drug, but also in that they dramatically ceased on reduction or discontinuation of the drug.
It was found that the drug also caused other pathological behavioral problems in the patients including compulsive eating, alcohol consumption besides an obsession with sex. Dr. Dodd of Mayo Clinic believes that it is a rare side effect, but also something every patient should know as it has the potential to cause personal or professional damage if not understood.
The results of study, which were reported online, is due for publication in the September issue of Archives of Neurology and questions the manner in which addictions work, raising the possibility of their treatment and cure. Parkinson's disease, the result of death of neurons in substantia nigra (part of the brain), is treated by enhancing the dopamine-signaling system. Dopamine a neurotransmitter and stimulant is responsible for regulating movement and balance, besides being crucial to the body's "reward" system with the capacity to reinforce various behaviors, some which may not be productive.
A 52-year-old Parkinson’s patient began to be "compulsive" after a raised dosage of the drug, to discover that his $100,000 gambling loss, 50 pound weight gain from binging and a sex-obsessed extramarital affair were all side-effects of his medicine. Of the patients evaluated at the Mayo clinic between 2002 and 2004, eleven started gambling after taking a dopamine agonist - either pramipexole or ropinirole.
It was noted that the gambling “habit” developed anywhere between one to three months of treatment or upto 12 to 30 months after starting the therapy. In eight of the eleven cases, the gambling ceased within months of the drug dose being reduced or withdrawn, while the other three patients were unavailable for further evaluation. Dr. Dodd who is lead author of the study said "This lends continued support towards the hypothesis that family of medicines may cause difficulty with behavioral issues in this population of patients".
It is believed that impulsive behaviors such as gambling or alcohol consumption, resulting in a feeling of pleasure even if undesirable, maybe the result of over-stimulating a part of the brain. Paul Sanberg, Director at the Center for Aging and Brain Repair, said "The fact that they were able to reduce the behavior by reducing or getting rid of the drug implies that it was the drug….and pretty well verifies that dopamine stimulation underlies these negative behaviors."
Up until now it was believed that only 5 percent of those taking pramipexole developed the side-effect of gambling. With more cases being reported, Neurologists are talking to patients about this possible side effect. At the same time Dr. Dodd says that dopamine agonists “is not a medication to throw away” as it is still a very responsive drug at lower doses for restless leg syndrome besides being used to treat Parkinson's disorder.
With the frequency of compulsive gambling being higher in those consuming pramipexole, researchers believe that the drug can provide clues into the nature of addictive behavior. While Dopamine, a brain chemical, sits on any of the many receptor sites in the brain, Pramipexole has an affinity for the receptor site D3, which is concentrated in the limbic areas of the brain responsible for emotions and internal reward systems.
The case study puts forth the exciting possibility of medications with the opposite effect on D3, capable of curbing addictive behaviors and therefore opening up an arena of treatment for compulsive behaviors.
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