Genetic Testing for Psychiatric Medication for GAD

DNA testing can help predict the best anxiety medication for you.
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Genetic testing for psychiatric medication for generalized anxiety disorder (GAD) is based on an area of research called "pharmacogenetics." In its simplest terms, this area of research involves studying how medications interact with inherited genes. 

In other words, people differ in their responses to different medications—both in terms of pharmacokinetics, how well a drug is metabolized, and pharmacodynamics, how well a drug works at its particular target in the brain—because of their unique genetic profile THE same drug might be perfectly safe for one person, but harmful to another.

If you've ever been prescribed psychiatric medication, you might know that it's not an exact science. Often it involves a process of trial and error, in which your doctor tries out a series of medications until the best one is identified. The objective of this new process of matching medication to your genetic profile aims to eliminate that period of trial and error.

Benefits of Genetic Testing for Psychiatric Medication

It's easy to imagine what the benefits could be of knowing what medications will work best for you before you ever take them. 

Dr. Jim Kennedy of the Centre for Addiction and Mental Health (CAMH) in Toronto, Canada described the potential benefits of genetic testing for psychiatric medication during a press conference about this new line of research:

"Using the genetic blueprint of our bodies... we can measure in the lab... and create a very easy-to-understand test that is provided to your doctor to help show what medications are very good for a particular patient, and what medications will not work well, and may have some nasty side effects."

In essence, genetic testing of this sort allows your doctor to personalize your anxiety treatment. This means that there will be less trial and error when prescribing medication for your symptoms. This may also result in an economic benefit, in that when the most helpful medication is prescribed, money isn't spent on other less helpful medications.

CAMH, in corporation with a genetics testing firm, is conducting ongoing research on this topic, led by Dr. Kennedy. The hope is that in the near future, every patient will have a personalized medication experience. This will also help to improve patient safety, as those at risk for adverse effects will be identified before being prescribed certain medications.

Research Findings

As reported at the World Congress of Psychiatric Genetics in Orlando, FL in October 2017, Tiwari and colleagues showed that genetic testing for psychiatric medication significantly improved the effects of treatment for generalized anxiety disorder, and reduced the use of benzodiazepines, a short-term medication for treating anxiety. Their findings were based on data from the Individualized Medicine: Pharmacogenetic Assessment and Clinical Treatment (IMPACT) study and the MEDCO dataset.

Steps in Genetic Testing for Psychiatric Medication

In the IMPACT Study, which is ongoing through CAMH, genetic testing is conducted through a saliva sample, similar to what you would submit to companies such as 23 and ME. The test can show how you will respond to various psychiatric medications and any side effects you might experience.

This is determined based on your genetic profile and how your body is expected to metabolize different medications.

Understanding Pharmacogenetics

Pharmacogenetics involves looking for variations in genes that may affect pharmacokinetics or pharmacodynamics. There is individual variability in the genes that affect how a drug is metabolized and how it works in the body. Some people might break down medications slowly, while other people might process them quickly. Side effects can be the result of a medication remaining in a high concentration in the body, because a person's doesn't metabolize them as quickly.

Barriers to Implementation

Quite simply, genetic testing for medication can be expensive if you do not have insurance coverage. In addition, availability of tests will be an issue until this type of testing becomes more mainstream. 

A Word From Verywell

It is important to note that in spite of research efforts like the ones outlined here, there is still not the kind of evidence (multiple randomized double-blinded studies) to support the consistent utility of these genetic tests in everyday clinical psychiatric practice. 

If you want to raise this topic with your doctor, ask how the available genetic tests might be potentially helpful in your particular treatment. Becoming an informed patient will help you to feel more in control of your prescriptions.

Sources:

Centre for Addiction and Mental Health. The Impact Study.

Centre for Addiction and Mental Health. CAMH and Assurex Health launch joint venture to advance personalized medicine in Canada

Healio Psychiatric Annals. GeneSight improves treatment response, decreases benzodiazepine use in anxiety.

Tiwari AK, et al. Combinational pharmacogenomic testing improves generalized anxiety disorder treatment response and decreases benzodiazepine use. Presented at: World Congress of Psychiatric Genetics; Oct. 13-17, 2017; Orlando, Florida.

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