New pharmacological and neuromodulation approaches for impulsive-compulsive behaviors in Parkinson's disease.

INTRODUCTION: A significant proportion of patients with Parkinson's disease (PD) display a set of impulsive-compulsive behaviors at some point during the course of illness. These behaviors range from the so-called behavioral addictions to dopamine dysregulation syndrome, punding and hoarding disorders. These behaviors have been consistently linked to the use of dopaminergic medications used to treat PD motor symptoms (dopamine agonists, levodopa, and other agents) and less consistently to neuromodulation techniques such as deep brain stimulation (DBS). Since there are still no approved treatments for these conditions, their pharmacological management is still a big challenge for clinicians.

METHODS: We conducted an extensive review of current pharmacological and neuromodulation literature for the management of impulsive-compulsive disorders in PD patients.

RESULTS: Pharmacological treatment approaches for impulsive-compulsive behaviors and DDS in PD patients include reduction of levodopa (LD), reduction/cessation of dopamine agonist (DA), and initiation of infusion therapies (apomorphine infusion and duodopa). Also, atomoxetine, a noradrenergic agent approved for the treatment of attention deficit hyperactivity disorder, showed some interesting preliminary results but there is still a lack of controlled longitudinal studies. Finally, while DBS effects on impulsive-compulsive disorders are still controversial, non-invasive techniques (such as transcranial magnetic stimulation and transcranial direct current stimulation) could have a potential positive effect but, again, there is still a lack of controlled trials.

CONCLUSION: Managing impulsivity and compulsivity in PD patients is still a non-evidence-based challenge for clinicians. Controlled trials on promising approaches such as atomoxetine and non-invasive neuromodulation techniques are needed.