Scientists show amphetamines help one of the main symptoms of ADHD
While it’s “fairly uncontroversial” among the medical community that amphetamines help with ADHD symptoms, no one knew for sure that it improved a key symptom – low motivation.
An Australian study has shown for the first time that common prescription amphetamines improve one of the main symptoms of ADHD: low cognitive and physical motivation.
Researchers from Monash University’s Turner Institute for Brain and Mental Health, The Alfred hospital and St Vincent’s Hospital tested 20 people with attention-deficit/hyperactivity disorder in effort-based decision-making on and off amphetamine-based medications (dexamfetamine and lisdexamfetamine).
They also did the same test on 24 healthy controls.
The study published in the Journal of Neuroscience found individuals with ADHD had lower motivation compared to those without ADHD.
It also found amphetamines increased motivation for both cognitive and physical behaviours in people with ADHD, and restored motivation for those with the condition to the level of healthy controls.
Around one in 20 Australians has ADHD, which is marked by inattention, impulsivity and overactivity.
In 2021, 441,201 PBS scripts were given out to both adults and children for dexamphetamine.
Lead author and Monash University associate professor Trevor Chong said while low motivation was critical to the diagnosis of ADHD, there was surprisingly no direct evidence to support those assumptions. There was also little evidence on whether amphetamines, used to treat the core features of ADHD, improved low motivation.
“We knew amphetamines did help with ADHD such as with clarity of thought and the ability to notice, but there was less data on their effects on motivation,” he said. “It’s the first empirical evidence … showing amphetamines actually have a very good effect in improving motivation in these individuals in ADHD to levels similar to control … It tells us we’re on the right path.”
He said it was still unclear, however, whether lower motivation in individuals with ADHD was linked to their difficulty concentrating and other cognitive symptoms.
Professor Chong said it gave medical professionals confidence in the sound basis for amphetamines to deal with motivation.
“The implications of this study are now making sure people stay on the medications, because when they went off it, they lost cognitive and physical motivation,” he said.
“It’s particularly important when you’re teaching someone something new and engaging in therapy to make sure … they’re motivated in treatments.”
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