Dopaminergic therapy disrupts decision-making in impulsive-compulsive Parkinsonian patients

Impulsive-compulsive behaviors (ICB) are common non-motor symptoms of Parkinson’s disease (PD). The relationship between these behaviors and dopaminergic drugs (DD) is still debated. The aim of this study is assessing the acute effects on economic decision-making of DD in Parkinsonian patients with and without ICB. PD patients with ICB (ICB+, n=14), without ICB (ICB-, n=16), and healthy controls (HC, n=12) performed twice a risk-based decision-making task with a learning component. The optimal strategy in the task was risk aversion. PD patients performed the task before DD intake (DD OFF) and repeated it after intake (DD ON). We found that during the first session, all groups progressively increased the fraction of low-risk choices. In DD ON condition ICB- patients retained their risk aversion strategy while ICB+ patients progressively regressed toward risky behavior. Within the ICB+ group, this effect correlated with levodopa equivalent daily dosage. We concluded that in ICB+ patients intake of DD acutely affects decision-making.