Pharmacogenetic testing versus standard prescribing of psychotropics for the treatment of severe mood disorders: A...

Major depressive disorder (MDD) and bipolar disorder (BD) are common, disabling conditions. Despite associated morbidity and premature mortality, current treatments have modest efficacy and response to treatment highly variable. Contributing factors to variability in response include influence of common genetic variations in the pharmacokinetic and/or pharmacodynamic action of medications. As such, attention has turned toward the identification of genetic markers that could assist with determining who will respond or not to psychotropic treatment. Results of studies to date are promising but primarily have been small. This study aims to evaluate the efficacy of a pharmacogenetic (PGx)-based decision support tool among adults with MDD and BD.

This single-site, single (rater) blinded, randomized controlled trial with two arms evaluates the 24-week efficacy of a PGx-based support tool for adults with MDD or BD. Participants are randomized to receive PGx testing or standard prescribing. Participants provide DNA samples at baseline, but only those (including clinicians) randomized to the former receive the results at the start of their study participation. It is not mandatory for clinicians to follow the test recommendations. Remission rate (primary outcome), change in depression symptoms, drop-out rate, medication adherence, and medication side effects (secondary outcomes) are assessed at 4-, 8-, 12-, and 24-week postbaseline by a blinded rater. Analyses will follow an intention-to-treat approach and use mixed models for repeated measures.

Treatment response to medication for severe mood disorders is highly variable and less than optimal. This trial will provide evidence as to whether a PGx-based support tool is an efficacious strategy to inform selection and dosing of pharmacotherapy among adults with severe mood disorders. Importantly, it will do so independently and with a larger sample size than previous studies.

This trial is registered under the number ACTRN12621001374853 (11 Oct 2021).