Methylphenidate increases willingness to perform effort in adults with ADHD

Pharmacol Biochem Behav. 2019 Aug:183:14-21. doi: 10.1016/j.pbb.2019.06.008. Epub 2019 Jun 18.

Abstract

Background: A reduced willingness to perform effort based on the magnitude and probability of potential rewards has been associated with diminished dopamine function and may be relevant to attention-deficit/hyperactivity disorder (ADHD). Here, we investigated the influence of ADHD status and methylphenidate on effort-based decisions. We hypothesized that ADHD participants would make fewer high-effort selections than non-ADHD subjects, and that methylphenidate would increase the number of high-effort selections. Furthermore, we hypothesized there would be associations among ADHD severity and methylphenidate-related changes in effort-based and attentional performance across all participants.

Methods and participants: ADHD (n = 23) and non-ADHD (n = 23) adults completed the Effort Expenditure for Rewards Task in which participants select between low-effort and high-effort options to receive monetary rewards at varying levels of reward magnitude and probability. A test of attentional performance was also completed.

Results: Overall, participants made more high-effort selections as potential reward magnitude and probability increased. ADHD participants did not make fewer high-effort selections than non-ADHD participants, but ADHD participants showed greater methylphenidate-related increases in high-effort selections. ADHD participants had worse attentional performance than non-ADHD participants. ADHD severity was associated with methylphenidate-related changes in high-effort selections, but not changes in attentional performance.

Conclusions: These results indicate that methylphenidate increases the willingness to perform effort in individuals with ADHD, possibly due to disorder-related motivational deficits. This provides support for theories of insufficient effort allocation among individuals with ADHD.

Trial registration: Clinicaltrials.gov Identifier, NCT02630017.

Keywords: Attention; Attention-deficit/hyperactivity disorder; Effort; Methylphenidate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Attention / drug effects*
  • Attention Deficit Disorder with Hyperactivity / drug therapy*
  • Attention Deficit Disorder with Hyperactivity / psychology
  • Central Nervous System Stimulants / administration & dosage
  • Central Nervous System Stimulants / therapeutic use*
  • Female
  • Healthy Volunteers / psychology
  • Humans
  • Male
  • Methylphenidate / administration & dosage
  • Methylphenidate / therapeutic use*
  • Motivation / drug effects
  • Neuropsychological Tests
  • Reaction Time
  • Reward*
  • Severity of Illness Index
  • Task Performance and Analysis
  • Young Adult

Substances

  • Central Nervous System Stimulants
  • Methylphenidate

Associated data

  • ClinicalTrials.gov/NCT02630017