Drug-Gene Tests: A New Way To Prescribe Psychiatric Medication

When prescribing medications and assessing treatment plans for patients, some psychiatrists are turning to genetic testing for help.

Drug-gene tests analyze genetic variations in DNA that can inform psychiatrists about genes that impact how a patient responds to certain medications. This may help them make more informed decisions when creating a treatment plan.

Dr. Samantha Meltzer-Brody is the chair of the Department of Psychiatry at UNC. She said drug-gene testing has the potential to be revolutionary when looking at the treatment of mood disorders like depression. With just a small saliva sample, Meltzer-Brody said drug-gene tests can help determine proper dosages for psychiatric medications by looking at the rate of which these medications are metabolized in the body.

“We know that people can have different genes for serotonin,” Meltzer-Brody said. “That can influence how quickly you metabolize – for example the drug fluoxetine, which is the generic name for Prozac. So you may be a slower metabolizer and I may be a faster metabolizer. If I’m a faster metabolizer that means a common dose that would be prescribed by a primary care doctor may not have much of an effect on me because I’m a faster metabolizer and I actually need a higher dose.”

The challenge in drug therapy is making sure a drug stays around long enough to do its job. However, some people have variable enzyme action so that they may metabolize the drug too quickly, too slowly or not at all.

“So we don’t all experience the same effects to any medication,” Meltzer-Brody said. “Some people are going to have different ways of metabolizing the drugs. You can have someone that metabolizes more quickly or more slowly and that may increase or decrease the risk that you will either respond to a certain dose or have side-effects.”

Meltzer-Brody said drug-gene testing provides a unique opportunity to prescribe a more accurate dosage of medication versus experimentation on the psychiatrist’s part – but that doesn’t mean these tests will tell a patient which drug to take.

“Those things [drug-gene tests] may help you refine treatment in a different way but none of them at this point in time tell you ‘this is the drug you should take’ or ‘this is what’s going to be the secret sauce.’” Meltzer-Brody said. “We are not there yet – partly because we do not yet understand the genetic signature of depression.”

While it can be tempting to think of drug-gene testing as a “cure-all” treatment, Meltzer-Brody wants the public to know that this process is still very much in development and there are still many limitations.

“We all have our DNA, but your DNA is greatly influenced by your life events, your exposures to different substances in the environment, your levels of stress and how your body works because of your unique life history,” Meltzer-Brody said. “All of those things have to be taken into consideration; not just looking at ‘here’s your DNA.’”

Further limitations such as cost and lack of insurance coverage confine drug-gene tests to select patients.

Meltzer-Brody said drug-gene testing is just one tool that can help determine the best route of care for a patient – but it shouldn’t be the only consideration when prescribing medication. She said healthcare providers need to look at the bigger picture when creating treatment plans.

“I think it’s exciting where the field is going,” Meltzer-Brody said. “I hope in 10 years we are in a very different place, and there’s reason to be optimistic about that, but we never will be able to let go of the enormous impact of our life events, of our stressors, of trauma, of exposures and the role that plays in how one person experiences illness versus someone else.”

Chapelboro.com does not charge subscription fees. You can support local journalism and our mission to serve the community. Contribute today – every single dollar matters.

Drug-Gene Tests: A New Way To Prescribe Psychiatric Medication

On Air Now: 97.9 FM