A variation in a gene called GRIK4 appears to make people with depression more likely to respond to the medication citalopram (Celexa) than are people without the variation, a study by the National Institute of Mental Health (NIMH), part of the National Institutes of Health, has found. The increased likelihood was small, but when people had both this variation and one in a different gene shown to have a similarly small effect in an earlier study, they were 23 percent more likely to respond to citalopram than were people with neither variation.

The finding addresses a key issue in mental health research: the differences in peoples responses to antidepressant medications, thought to be based partly on differences in their genes. Some patients respond to the first antidepressant they attempt, but many dont. Each medication takes weeks to exert its full effects, and patients depression may worsen while they search for a medication that helps. Genetic studies, such as the one described here, may lead to a better understanding of which treatments are likely to work for each patient.

Results of the study are in the August issue of the American Journal of Psychiatry, reported by lead researcher Francis J. McMahon, MD, Silvia Paddock, PhD, of NIMH, and colleagues. Scientists from the National Human Genome Research Institute, the National Institute on Alcohol Abuse and Alcoholism, Mount Sinai School of Medicine, and University of Texas Southwestern Medical Center also contributed to the research.

Were moving steadily closer to being able to personalize treatments based on patients genetic variations. This is a crucial need for the millions of Americans who suffer from depression, said NIMH Director Thomas R. Insel, MD. New techniques have led to advances that would have been inconceivable a few years ago and are making individualized treatment an achievable goal.

The researchers studied DNA provided earlier by patients participating in a recently comp
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Contact: Susan Cahill
scahill@mail.nih.gov
301-443-4536
NIH/National Institute of Mental Health
1-Aug-2007