According to the University of Calgary (U of C), up to 50 per cent of children, adolescents, and young adults who take medication for moderate-to-severe mental health conditions or neurodevelopmental disorders will not respond or experience burdensome adverse drug reactions to these medications.1 Current use of mental health-related medications (e.g., antidepressants, antipsychotics) in children can be best described as a trial-and-error process that can impact the wellbeing of those taking the medications and their families. This trial-and-error process could, in part, be avoided through pharmacogenetic testing, a specific type of genetic testing that has the potential to improve drug efficacy and reduce the morbidity, mortality, and cost associated with adverse drug reactions.
The U of C is conducting a new research program called Pharmacogenetic-Supported Prescribing for Kids (PGx-SParK). The aim of the project is to implement and evaluate an evidence-based pharmacogenetic testing service to improve drug treatment outcomes in children, adolescents and young adults receiving mental health care.
“When I arrived in Alberta four years ago from Australia, I was slightly surprised there wasn’t much happening in pharmacogenetics for children and adolescents here, particularly for mental health,” said principal investigator Chad Bousman, Associate Professor of Medical Genetics at the U of C. “If you look at the proportion of children taking selective serotonin reuptake inhibitors (SSRIs) or any kind of psychiatric medication, it’s astronomical. Clinical trials have shown that pharmacogenetic-supported prescribing has worked in adults, so why not apply it for children? That was the rationale for doing the study.”
Children, adolescents, and emerging adults between the ages of six and 24 and who are starting or switching a psychiatric medication are eligible to participate with support from their physician.
“Having the physician on board is important because we are providing results that can potentially help with prescribing decisions,” said Chad. “We don’t want to provide test results that end up in the bin because the doctor doesn’t think it’s worthwhile. We also don’t want to damage the relationship between the patient and the physician. If the doctor is on board and the patient agrees, we move forward.”
Participation in the program involves providing a saliva sample using a collection kit sent to the patient’s home and completion of six web-based questionaries over a six-month period. Once the test results are available, the doctor and the patient’s family discuss how they can apply the results.
Chad says the test determines how certain drugs would be metabolised by the patient. If metabolised too slowly, certain drugs may build up and adversely affect the patient, while those metabolised too quickly will not provide the desired effect. This can help with the trial and error that often occurs with prescriptions for mental health conditions.
“We’re testing for genetic variations in enzymes that sit in the liver for the most part,” says Chad. “It helps determine how much of the drug is getting to the brain. Once it gets in the brain, it’s still a bit of a black box with what’s happening, and we don’t have genetic markers to help guide us. Using the genetic markers we do have, we can help rule out certain medications and essentially narrow the list of medications to choose from. It’s challenging, but having just that information, the clinical trials in adults have shown that it increases the probability of prescribing the right drugs. For antidepressant prescribing, patients who participate in pharmacogenetic testing are 71 per cent more likely to have symptom remission.”2
Chad hopes to raise awareness amongst pharmacists about the PGx-SParK program, so that pharmacists can recommend eligible patients to discuss potential participation with their physicians. Chad is also proposing a partnership between the U of C and the University of Alberta to provide pharmacist-delivered pharmacogenetic testing for adults with mental health conditions.
- Pharmacogenetic-Supported Prescribing for Kids, University of Calgary, https://www.psychpgxlab.com/projects/pgx-spark, retrieved on April 6, 2022. ↩︎
- Arandjelovic, Katrina, Chad Bousman, Boadie Dunlop, Harris Eyre, and Serafino Mancuso. “Pharmacogenetic tests and depressive symptom remission: a meta-analysis of randomized controlled trials,” 2018. ↩︎
