Brain and genes to improve anxiety treatment

Right now, about half of all people who take medicine for an anxiety disorder don’t get much help from it. And doctors have no definitive way to predict who will, and who won’t, benefit from each anti-anxiety prescription they write.

But a University of Michigan Medical School researcher and his team are working to bring more certainty to how doctors and patients choose anxiety treatments, by probing the connection between brain activity, genetics and medication.

In a paper last month in the Journal of Neuroscience, K. Luan Phan, M.D., and his former University of Chicago colleagues reported intriguing findings from a brain imaging study in occasional, non-dependent, marijuana users.

In a placebo-controlled design, they made the findings after giving the volunteers delta-9-tetrahydrocannabinol (THC), the active ingredient in marijuana, and exposing them to photographs of emotional faces, which served as signals of social communication. The study results, which showed that THC reduces the response to threat in a brain region called the amygdala, allowed the researchers to zero in on an area of the brain that might serve as a good target for new anti-anxiety drugs.

Now, with a new clinical trial that is currently seeking participants, Phan is searching for more clues as to how anxiety treatment could be tailored to the individual patient, to give the best chance that a treatment will work for him or her.

The new study will test a generic form of the drug Zoloft (sertraline), a selective serotonin reuptake inhibitor (SSRI) approved by the U.S. Food and Drug Administration for social anxiety disorder and other anxiety disorders. Both people with social anxiety disorder and a comparison group of people without anxiety are needed for brain scanning and genetic testing.

The idea is to see whether variations in the genes for certain brain receptors and transporters are linked with variations in how a person’s brain reacts to pictures of emotional faces, and variations in how they respond to the anti-anxiety drug. This information could lead to an individualized or personalized approach to medical care.

“These two studies are trying to get to the same goal: to find better treatments for anxiety disorders that affect millions of Americans and seriously interfere with their functioning,” says Phan, an assistant professor of psychiatry at U-M and the VA Ann Arbor Healthcare System. “The cannabis study highlights a new avenue that we need to explore further as we try to develop novel medications, while the sertraline study will try to find out if we can tell which patients might or might not respond well, and by what mechanism, to an already existing medication known to have some efficacy in treating anxiety disorders.”

Reference: Journal of Neuroscience, March 5, 2008, Vol. 28, No. 10, 2313-2319

Source: University of Michigan Health System, USA



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