Amphetamines Improve the Motivation to Invest Effort in Attention-Deficit/Hyperactivity Disorder.
Level 2 - randomized trial
Counterbalanced crossover experimental study in ADHD patients with a healthy control comparator group.
PubMed 37666665 · doi:10.1523/JNEUROSCI.0982-23.2023
What was done
Researchers investigated effort sensitivity and the effect of stimulant medication in 20 adults with ADHD (11 males, 9 females) routinely treated with amphetamines (dexamfetamine or lisdexamfetamine) compared to 24 healthy controls (8 males, 16 females). Participants with ADHD completed two counterbalanced testing sessions: one ON and one OFF their prescribed medication. During each session, participants performed an effort-based decision-making task measuring their willingness to invest varying levels of cognitive or physical effort in exchange for monetary rewards.
What was found
The abstract reports directional findings without specific numerical values, percentages, or test statistics. Individuals with ADHD OFF medication showed lower motivation to invest effort in both cognitive and physical domains compared to healthy controls. Administration of amphetamine medication increased motivation uniformly across both effort domains, restoring motivation levels in the ADHD cohort to levels comparable to healthy controls.
Why it matters
This study provides experimental evidence that motivational deficits in ADHD encompass both physical and cognitive effort aversion, rather than being confined to specific cognitive tasks. It demonstrates that catecholaminergic stimulation with amphetamines directly modulates and normalizes domain-general effort valuation in ADHD.
Limits
The abstract reports no exact numerical data, effect sizes, or confidence intervals. The sample size was relatively small (20 ADHD participants, 24 controls). The cohort was restricted to individuals already successfully managed on amphetamines, which may introduce selection bias toward treatment responders, and long-term real-world behavioral outcomes were not evaluated beyond the laboratory task.
Cited by
- supports Physical movement and cognitive effort are governed by the same catecholamine systems, primarily dopamine, with norepinephrine and epinephrine generating focus.