UCalgary study aims to use genetic testing to predict response to ADHD medication

Medication is a standard treatment for children diagnosed with ADHD (attention deficit hyperactivity disorder). However, prescribing medications for ADHD is a process of trial and error, as doctors have difficulty predicting who will respond well to which type of medication and who may experience side effects.  This is often a frustrating journey for parents and their children who may have to experience many doctor visits, trying two to three types of medication before finding one that works. 

But the future could look different. Imagine taking your child to a doctor’s office, providing a saliva sample for a DNA test and getting an accurate printout of what medications and dosage they should take to help with their ADHD.  This is the idea behind a type of personalized medicine known as pharmacogenetic testing – choosing medications based on your genes.  Led by Dr. Chad Bousman, PhD, the Psychiatric Pharmacogenomics Lab at the University of Calgary is conducting a study to find genetic variants that can predict ADHD stimulants response and side effects. The goal is to develop clinical genetic guidelines in the next decade that transform how ADHD is managed.

Graduate student Sam Siu is at the centre of this research. With a master’s degree in health data science, Siu brings her expertise to the lab by analyzing massive genetic datasets. When study participants send in saliva samples, the lab extracts DNA and converts it into digital files—where she reviews the data for quality, studies thousands of genetic markers, and looks for patterns that might explain why some children and youth respond better to ADHD medications than others. “We’re the first Canadian study, and one of the very few global studies, to use genome-wide genotyping to look at how people respond to ADHD stimulants,” says Siu. “This kind of data analysis could be the future of health care.”

She says the idea of using genetic markers to guide treatment for ADHD stimulants is very possible, explaining that “health-care systems are already using genetic information to guide treatment in areas of heart disease, psychiatry, and cancer care.”

Siu is one of many students and trainees working in Bousman’s Pharmacogenomics Lab.  

“Our trainees are the driving force behind every discovery we make,” says Bousman, a professor in the Cumming School of Medicine. “They bring fresh ideas, technical expertise, and an incredible curiosity that pushes the science forward. Investing in their training isn’t just about building careers—it’s about shaping the future of precision medicine.”

Study Recruitment

In addition to genomic analysis, Siu’s role as a graduate student is to help recruit people for studies in the Bousman lab.  Currently, she is recruiting 400 people for their  study, which offers free pharmacogenetics testing (PGx- STaR study)  to children and youth who have been diagnosed with ADHD and are about to start a methylphenidate medication, such as Ritalin – a first-line medicine for ADHD.

Participants between the ages of 6-24 are being recruited from the western provinces including Alberta, British Columbia, Saskatchewan and Manitoba.  

Participants in the study will receive a personalized pharmacogenomics report. However, because researchers have not yet identified which genes predict positive responses to specific ADHD medications, the report will only highlight medications for other conditions that may align with the participant’s genetic profile. “While we can't yet pinpoint which genes influence ADHD medication outcomes, every participant helps move us closer to that goal. Anyone who participates in this study will help families down the road,” says Siu.