Genes Can Impact Depression Treatment

(HealthDay News) -- U.S. researchers say they've spotted genetic variations that affect how patients respond to antidepressants.

"Medications to treat depression are widely available, but no one treatment works for everyone. Additionally, it can be difficult to predict which patients will experience harmful or unpleasant side effects," Dr. Francis McMahon, chief of Genetic Basis of Mood & Anxiety Disorders at the U.S. National Institute of Mental Health explained in a prepared statement.

"We are seeking to better understand why this is the case and, using genetic markers, develop personalized treatments that give patients the best chance at remission," McMahon said.

For this study, which included more than 1,900 people with major depression, researchers examined the effects that polymorphisms (common differences in DNA sequences) of 68 genes had on depression treatment effectiveness and side effects. The patients were treated with the antidepressant citalopram for at least six weeks.

Polymorphisms in a gene that regulated serotonin were associated with treatment outcome, the team found. People who carried two copies of the polymorphism were 18 percent more likely to respond to antidepressant treatment than patients who didn't have two copies, McMahon said.

Polymorphisms in two other genes -- a protein involved in neurogenesis and a receptor for the brain chemical glutamate -- also influenced the effectiveness of the antidepressant, the study said.

Patients with all three response-associated polymorphisms were 40 percent more likely to respond to treatment than patients with none of the polymorphisms.

The findings were slated for presentation Wednesday at the annual meeting of the American College of Neuropsychopharmacology.

"Ultimately, our goal is to put together a panel of genetic markers that can guide treatment decisions and help doctors choose an antidepressant that will work best for an individual patient," McMahon said.

More information

The American Academy of Family Physicians has more about depression.