Pharmacogenomics and the Treatment of Major Depression
Major depressive disorder is a leading cause of disability worldwide and is often one of the most difficult conditions to treat. Too often, trial-and-error medication therapy has been the only avenue to treat a condition that has dramatic and detrimental effects on an individual and their families. Despite an increase in the number of medications available to treat depression, medication therapy response is still far from optimal, side-effect rates are often unacceptable and costs continue to mount without effective therapy. Healthcare providers have been searching for a better way and a Spanish study shows the dramatic and positive effect of evaluating the drug gene interaction and prescribing accordingly.
Common genetic variation has been estimated to account for 42% of antidepressant response, especially originating in the Cytochrome P450 family of genes (especially CYP2D6 and CYP2C19) and the serotonin genes (SLC6A, HTR2C, HTR2A) and the ABCB1 transporter gene. The 12-week study showed a 34% increase in the medication response rate over treatment as usual and a significant improvement in depression rating scores (Hamilton Depression Rating Scale).