A study in the recent Archives of Neurology documents the connection between certain Parkinson’s disease medications and a significant increase in the likelihood of an impulse-control disorder in the form of buying, gambling, eating, or sex. The drugs at issue are dopamine agonists, a class of pharmaceuticals that ease the difficult and frustrating motor symptoms associated with Parkinson’s. But patients who took these drugs showed a rate of impulse-control disorders 2–3.3 times greater than patients not taking them, and among the disorders, compulsive buying was the most common. Though dopamine seems clearly to be at the center of whatever process is going on, very little about the mechanism is fully understood; and what we do understand suggests that the issue is quite complex.
The study serves to remind us that a shopping habit may have many components, some of them, perhaps, chemically identifiable. As we learn more about the role (or roles) of dopamine, we may approach the neurological ground level of reward and compulsion. And just conceivably, although treatment of compulsive shopping with drugs has thus far had only mixed results, there may, in time, be a more effective protocol.