In this pilot within-subject crossover placebo-controlled study, subjects with a diagnosis of Parkinson's Disease who have recently experiencing an impulse control disorder will be enrolled. Subjects will randomized to one of two treatment groups. During the first portion of the study, the first treatment group will receive transdermal nicotine (nicotine by skin patch) and the second treatment group will receive an identical placebo patch which does not contain any nicotine. Over the course of the study, each of the two groups will switch to receive whichever treatment they were not initially receiving (for example-the first treatment group will later receive the placebo patch and the second treatment group will later receive the nicotine patch). Each treatment group will receive the nicotine patch or placebo patch for an equal number of weeks, but at different times during the study. Clinical and laboratory computer based measurements of impulsive and compulsive behaviors, memory testing, sleep quality/ sleepiness, and Parkinson's disease symptoms will be assessed at each visit.