Pharmacogenomic Testing in Depression: A 2021 Update

Key Messages

• An update to a 2020 CADTH Rapid Review was conducted to capture new literature published since 2019 examining the effectiveness of drug treatment informed by genetic testing compared to usual care for adults with depression.
• Eleven studies were identified: 1 systematic review, 1 health technology assessment, 4 randomized controlled trials reported in 5 publications, 1 non-randomized study, 1 cohort study with historical control, and 2 uncontrolled before-and-after studies.
• Similar to the conclusions of the 2020 CADTH report, the effectiveness of gene testing for treating depression was unclear. In patients with depression, some studies showed that there were improvements in the clinical effectiveness outcomes in those who received gene testing and other studies showed that there was no difference in outcomes between those who received gene testing and those who did not. No studies showed that gene testing resulted in worse outcomes compared to those who did not receive gene testing.
• In the current report, the were several limitations across studies such as poor design, inclusion of subjectively measured outcomes, small sample sizes, and a focus on hospital settings ― all of which may not be generalizable to other populations.