Beschreibung:
<jats:p>The development of impulse control disorders (<jats:styled-content style="fixed-case">ICD</jats:styled-content>s) in Parkinson's disease (<jats:styled-content style="fixed-case">PD</jats:styled-content>) may arise from an interaction among cognitive impairment, impulsive responding and dopaminergic state. Dopaminergic state may be influenced by pharmacologic or genotypic (catechol‐<jats:italic>O</jats:italic>‐methyltransferase; <jats:styled-content style="fixed-case">COMT</jats:styled-content>) factors. We sought to investigate this interaction further by comparing those with (<jats:italic>n</jats:italic> = 35) and without (<jats:italic>n</jats:italic> = 55) <jats:styled-content style="fixed-case">ICD</jats:styled-content>s on delay‐discounting in different pharmacologic conditions (<jats:styled-content style="fixed-case">ON</jats:styled-content> or <jats:styled-content style="fixed-case">OFF</jats:styled-content> dopaminergic medication) and on response inhibition as well as aspects of executive functioning in the <jats:styled-content style="fixed-case">ON</jats:styled-content> state. We then undertook an exploratory sub‐group analysis of these same tasks when the overall <jats:styled-content style="fixed-case">PD</jats:styled-content> group was divided into different allelic variants of <jats:styled-content style="fixed-case">COMT</jats:styled-content> (<jats:italic>val/val</jats:italic> vs. <jats:italic>met/met</jats:italic>). A healthy control group (<jats:styled-content style="fixed-case">HC</jats:styled-content>;<jats:italic> n</jats:italic> = 20) was also included. We found that in those with <jats:styled-content style="fixed-case">PD</jats:styled-content> and <jats:styled-content style="fixed-case">ICD</jats:styled-content>s, ‘cognitive flexibility’ (set shifting, verbal fluency, and attention) in the <jats:styled-content style="fixed-case">ON</jats:styled-content> medication state was <jats:italic>not</jats:italic> impaired compared with those without <jats:styled-content style="fixed-case">ICD</jats:styled-content>s. In contrast, our working memory, or ‘cognitive focus’, task was impaired in <jats:italic>both </jats:italic><jats:styled-content style="fixed-case">PD</jats:styled-content> groups compared with the <jats:styled-content style="fixed-case">HC</jats:styled-content> group when <jats:styled-content style="fixed-case">ON</jats:styled-content>. During the delay‐discounting task, the <jats:styled-content style="fixed-case">PD</jats:styled-content> with <jats:styled-content style="fixed-case">ICD</jats:styled-content>s group expressed greater impulsive choice compared with the <jats:styled-content style="fixed-case">PD</jats:styled-content> group without <jats:styled-content style="fixed-case">ICD</jats:styled-content>s, when in the <jats:styled-content style="fixed-case">ON</jats:styled-content>, but not the <jats:styled-content style="fixed-case">OFF</jats:styled-content>, medication state. However, no group difference on the response inhibition task was seen when <jats:styled-content style="fixed-case">ON</jats:styled-content>. Finally, the <jats:italic>met</jats:italic> homozygous group performed differently on tests of executive function compared with the <jats:italic>val</jats:italic> homozygous group. We concluded that the disparity in levels of impairment among different domains of executive function and impulsive decision‐making distinguishes those with <jats:styled-content style="fixed-case">ICD</jats:styled-content> in <jats:styled-content style="fixed-case">PD</jats:styled-content> from those without <jats:styled-content style="fixed-case">ICD</jats:styled-content>, and may in part be affected by dopaminergic status. Both pharmacologic and genotypic influences on dopaminergic state may be important in <jats:styled-content style="fixed-case">ICD</jats:styled-content>.</jats:p>