Dissecting the effects of disease and treatment on impulsivity in Parkinson's disease

J Int Neuropsychol Soc. 2012 Nov;18(6):942-51. doi: 10.1017/S135561771200094X. Epub 2012 Oct 19.

Abstract

Converging evidence, including observations in patients with Parkinson's disease (PD), suggests that dopamine plays a role in impulsivity. This multi-faceted construct includes considerations of both time and risk; determining how these more specific processes are affected by PD and dopaminergic treatment can inform neurobiological models. We examined the effects of PD and its treatment on temporal discounting and risky decision-making in a cohort of 23 mild-moderate PD patients and 20 healthy participants. Patients completed the Balloon Analogue Risk Task and a temporal discounting paradigm both on and off their usual dopamine replacement therapy. PD patients did not differ from controls in their initial risk-taking on the Balloon Analogue Risk Task, but took progressively more risks across trials when on medication. A subset of patients and controls was tested again, 1.5-3 years later, to explore the effects of disease progression. On follow-up, baseline risk-taking diminished in patients, but the tendency to take increasing risks across trials persisted. Neither disease progression nor its treatment affected the temporal discounting rate. These findings suggest a different neural basis for temporal discounting and risk-taking, and demonstrate that risk-taking can be further decomposed into initial and trial-by-trial effects, with dopamine affecting only the latter.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antidepressive Agents / therapeutic use
  • Antiparasitic Agents / therapeutic use*
  • Cognition Disorders / drug therapy
  • Cognition Disorders / etiology
  • Female
  • Humans
  • Impulsive Behavior / drug therapy*
  • Impulsive Behavior / etiology*
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Neuropsychological Tests
  • Parkinson Disease / complications*
  • Parkinson Disease / drug therapy*
  • Risk-Taking
  • Severity of Illness Index

Substances

  • Antidepressive Agents
  • Antiparasitic Agents