Pharmacogenetic-Guided Antidepressant Prescribing (PGx-GAP) in Adolescents


Depression is common and has serious effects on adolescents and their families. While ~ 150,000 Canadian adolescents take antidepressant medications each year, many do not feel better with medication. Some adolescents can react badly to the medication - a side effect or adverse reaction - and some adolescents do not have an improvement in their depression.

Prescribing medication is often a ‘trial-and-error’ process, where adolescents take a medication for a month or more to see if it will work. If it does not work, they might repeat this process with another medication.

Our team aims to address the trial-and-error approach to prescribing medications. We want to evaluate a new way to match adolescents to an antidepressant medication that is more likely to be safe and beneficial for them. We will enrol adolescents into a study that uses a small amount of their saliva to conduct a single genetic test.

The results from this test show whether:
1) their genes might make it harder for their body to process some antidepressant medications (causing unexpected side effects or adverse reactions), or
2) their genes may cause their body to process an antidepressant medication too fast, which means they may not benefit from that medication or may need a higher dose to benefit. We want doctors to use these genetic test results when they make a decision about which medication to prescribe.

Because we do not know if this approach will work for adolescents yet, we need to compare it with usual prescribing practices. A random half of the participants in this study will receive a report based on their genetic test and a random half will receive a report based on usual prescribing guidelines. All participants will receive a full pharmacogenetic report at the end of the study.


Currently recruiting participants: Yes

Eligible gender: Male, Female, Transgender, Other

Eligible ages: 12 to 17

Inclusion criteria:

1. Have already tried fluoxetine (Prozac) for depression
2. Main diagnosis is depression
3. Current depression symptoms are at the study cut-off level (determined with a set of questions our research team will ask over the phone)
4. Plan to start a new medication for depression
5. Fluent in English

Exclusion criteria:

1. Diagnosis of psychosis, bipolar disorder, eating disorder, autism spectrum disorder, fetal alcohol spectrum disorder, or intellectual disability
2. Monthly or more frequent use of alcohol/substances, other than cannabis and tobacco
3. Have already tried 3 or more antidepressant medications
4. Started therapy or brain stimulation in the previous 8 weeks, or plan to start/change these in the next 12 weeks (You are encouraged to continue with your current treatment while in the study. We only want to avoid changes in treatment that will make it hard to know if any changes in depression are due to medication or changes in therapy/brain stimulation during the study).
6. History of liver or bone marrow transplant
7. History of pharmacogenetic testing


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Principal investigator:

Chad Bousman

Clinical trial: