Impulsive and compulsive behaviors in Parkinson's disease

Abstract

Impulsive-compulsive behaviors (ICBs) in Parkinson's disease (PD) are a common and devastating side effect of dopamine replacement therapy. In this review we describe the phenomenology, prevalence, and risk factors of patients with PD. Results of behavioral studies assessing the neuropsychological profile of patients with PD emphasize that the ICBs, which are behavioral addictions, are not hedonically motivated. Rather, other factors such as the inability to cope with uncertainty may be triggering ICBs. New insights from functional imaging studies, strengthening the incentive salience hypothesis, are discussed, and therapeutic guidelines for the management of ICBs in PD are given.

Figure 1

A: Two cups were presented with the blue cup containing more blue than green beads and the green cup more green than blue beads. One bead was drawn and showed to the participant. They could either ask for up to 10 additional draws before deciding or immediately guess the cup, from which they thought the bead was drawn. B: Two different ratios were used. One 60/40 ratio (above) and one 80/20 split (below).

Figure 2

Results of the beads task demonstrate 3 distinct groups with both control groups drawing significantly more beads than all patients. PD patients without ICBs (PD-ICBs) resembled pathological gamblers, whereas PD patients with ICBs (PD+ICBs) performed similarly to substance abusers. One bead is always shown at the start of the task, so total beads seen are mean draws plus one. Significant differences (p<0.001) are labelled with “**”.