Study finds sharp rise in prescriptions for stimulant medications used to treat ADHD

A new Ontario-based study has found a significant rise in prescriptions for stimulant medications used to treat attention-deficit/hyperactivity disorder (ADHD), particularly among adults and females. The study, published in JAMA Network Open, calls for better clinical guidance to help ensure those medications are prescribed appropriately, and to help prevent possible adverse health effects, such as heart conditions. 

ADHD is a common neurodevelopmental condition that affects attention and impulse control, impacting about five per cent of the population. 

Researchers from The Hospital for Sick Children (SickKids) and North York General Hospital analyzed provincial data covering more than 15 million residents, of whom nearly 600,000 received prescriptions for ADHD stimulants, such as methylphenidate and amphetamines. This study found a 157 per cent increase from 2015 to 2023, with the sharpest growth beginning in 2020. 

Individuals, particularly adults, are receiving ADHD drug prescriptions at rates we have not seen before. While stimulant medications can improve outcomes for those with ADHD, enhanced clinical training and prescribing as per evidence-based guidelines for diagnosis and treatment are essential."

Dr. Yaron Finkelstein, Staff Physician, Senior Scientist in the Child Health Evaluative Sciences program, Canada Research Chair in Pediatric Drug Safety and Efficacy, and the study's senior author

Notable increases in prescriptions among adults and females 

The research team analyzed data from Ontario's Narcotics Monitoring System, tracking all stimulant prescriptions dispensed to more than 15 million residents aged 5 to 105. They found that the annual rate of stimulant prescriptions for ADHD rose from 275 to 708 per 100,000 people from 2015 to 2023, with the yearly growth rate jumping to 29 per cent after the start of the COVID-19 pandemic. 

ADHD has traditionally been viewed as a condition diagnosed primarily in school-aged children, with a predominance among males. The study shows a marked shift among adults, particularly females aged 18 to 44, who have experienced the most significant increases in diagnoses. By 2023, first-time ADHD diagnoses among adults aged 45 to 64 rose sharply, and females in the 18 to 44 age groups were receiving new stimulant prescriptions at a rate more than 200 per cent higher than males. 

The authors note increased awareness and easier access to diagnosis, including through virtual platforms, may contribute to this rise. Other factors include possible misdiagnosis or overdiagnosis, and the social acceptability and environmental changes brought on by the COVID-19 pandemic. 

"The upward trend in prescriptions around the world highlights an important challenge," says Dr. Daniel Myran, a family physician, ICES scientist, and Gordon F. Cheesbrough Research Chair in Family and Community Medicine at North York General Hospital. "On one hand, it is likely showing progress towards identifying and treating ADHD in groups who have historically been underdiagnosed. However, the scale of the increases also raises concerns about mis- or over-diagnosis, which can result in exposure to adverse side effects of medications and a missed opportunity to treat other mental health conditions." 

The pandemic saw major shifts in work, recreation, social isolation and media use, all of which can be associated with increased ADHD symptoms, but research into whether these prescriptions are always appropriate is limited. 

"With around seven per cent of children and a nearly three-fold increase in adults being prescribed stimulants for ADHD than before the pandemic, ongoing research and clear clinical guidance is essential to ensuring these medications are used safely and appropriately," says Finkelstein. 

This research was supported by ICES, Canadian Institutes of Health Research (CIHR), Canada Research Chairs Program, and SickKids Research Institute.