Impulse control disorders in Parkinson's disease.

Impulse control disorders (ICDs), a group of complex behavioral disorders, occur more commonly in Parkinson's disease (PD) patients than in the general population, with a reported prevalence up to 13.6% in some studies. The most common ICDs reported are pathological gambling (PG), hypersexuality (HS), compulsive shopping and compulsive eating. More than a quarter of the patients with ICDs have 2 or more behavioral addictions. These abnormal behaviors impair activities of daily living and have a negative impact on quality of life of patients and their families. As with many other non motor symptoms in PD, ICDs are frequently under-reported by patients and caregivers and may be under-recognized by the treating physicians. Treatment with dopamine agonists (DA) is the main risk factor for developing ICDs, and stimulation of mesolimbic D3 receptors by DA is thought to underlie their development. The DA effect seems to be a class effect and not specific for any DA. Levodopa can also induce ICDs but much less so than the DAs. The management of ICDs in PD is complex. Modifications in dopaminergic drug treatment are frequently necessary. In some cases alternative therapies such as atypical antipsychotics, antidepressants or deep brain stimulation if motor symptoms become incapacitating after adjustment of dopamine replacement therapy should be considered.