Helping Doctors Make Better Decisions: New Genetic Test May Help Physicians Choose the Most Effective Antidepressant Medications for Patients

Study shows that genetic test led to improvement in outcomes for patients with Major Depressive Disorder

NEW YORK — Dr. John Greden, M.D., executive director of the University of Michigan Comprehensive Depression Center presented findings from a new study at the American Psychiatric Association’s annual meeting in New York City on May 7. The research is being presented in a poster session and is titled, “Combinatorial pharmacogenomics significantly improves response and remission for major depressive disorder: A blinded, randomized control trial.” Findings show that patients were 50 percent more likely to achieve remission and 30 percent more likely to respond to treatment and when their medication selection was guided by the commercially available GeneSight Pharmacogenomic test. Dr. Greden served as principal investigator of the study in his unpaid consultant role with Assurex Health, which made the test and is part of Myriad Genetics.

John Greden, M.D.

Pharmacogenomics refers to the branch of pharmacology concerned with the effect of genetic factors on metabolism and distribution of medications. By looking at patient’s individual genetic makeup, the hypothesis is that physicians may be able to more accurately and effectively treat their patients.

This 24-week study included over 1,100 patients with moderate-to-very severe depression who had failed to get relief from at least one antidepressant medication, and actually had an average of more than 3 medications they had tried. Patients were divided into two treatment arms: the test arm (n=560) in which clinicians used the genetic test results to guide treatment decisions, and a treatment-as-usual arm (n=607) in which psychiatrists and primary care physicians prescribed medication as they normally would without the benefit of genetic testing. The Hamilton Depression scale (HAM-D17) was used to measure the key endpoints of remission (achieving a HAM-D17 score <7), response (50 percent decrease in HAM-D17 from baseline) and symptom improvement (percent change in HAM-D17 from baseline) at week 8. The durability of patients’ mental health outcomes was assessed at week 24.

“This is the first-ever prospective, large-scale, blinded, randomized controlled trial evaluating combinatorial pharmacogenomics testing in patients with treatment-resistant major depressive disorder,” Greden says. “GeneSight-guided care was compared to physicians’ optimized treatment plans or “Treatment as Usual (TAU)”. The results indicate that patients fared significantly better with the pharmacogenomics approach than with usual care, despite this being a difficult-to-treat patient population. The improvements continued to increase as the study was extended to 24 weeks.”

“This method is not foolproof yet, but it shows promising results,” Dr. Greden added. “Hopefully, more physicians will be able to incorporate this test in their practices, and have the results in hand before patients are prescribed medications.”

The poster for this study will be presented on Monday, May 7 at 10:00 a.m. in P5-110 within the Javits Center. Further results have been submitted to The American Journal of Psychiatry and are being reviewed for publication.


Established in 2001, the University of Michigan Comprehensive Depression Center (UMDC) is the first of its kind devoted entirely to bringing depression into the mainstream of medical research, translational care, education, and public policy. It is comprised of nearly 350 members from 17 colleges, centers, and institutes across the University of Michigan. The Center is at the forefront in changing the paradigm of how depression and bipolar illnesses are understood and treated. Learn more: