I receive so many questions from my patients about pharmacogenetics testing. Many patients ask if the testing results can guarantee the right medication to prescribe that will effectively treat their depression. Other individuals are worried about the cost, and question if insurance will cover the testing.
To answer these questions, it is important to understand that the pharmacogenomic testing is simply another tool in the decision of what medication will best work for a patient. Some insurance companies will cover some of the testing cost, and other companies will not. It is important that individuals check with their insurance company to verify their benefits before ordering the test.
How does pharmacogenomic testing work?
It is important to have a basic understanding of what pharmacogenic testing entails. Here is some background information to help explain the process further.
Genes are the human body’s blueprint to build cells and organs. Genetic testing allows us to learn how the inherited genes in the DNA of an individual might affect their health. Pharmacogenetic (also known as pharmacogenomic) refers to testing a person’s genetic makeup to see how their body processes different medications.
In some cases, when an individual has tried multiple medications without improvement, a prescriber might order this testing to get more information about a patient’s genetic make-up. The testing will look at some of the genes responsible for metabolizing drugs, and it will tell an individual what kind of metabolizer (ie: normal, intermediate, slow, rapid) they are.
The test results will be used in combination with information from the patient’s past treatment to make decisions about future medications. To obtain the DNA for testing, the patient’s cheek is swabbed, and the sample is sent to a lab to process the genetic information.
What is the end goal?
The aim of the testing is to ultimately help guide psychiatric medication treatment; not necessarily dictate a specific treatment.
Pharmacogenetic testing CAN tell your prescriber:
- How quickly your body might process a medication
- How effectively your body might process a medication
Pharmacogenetic testing CANNOT tell your prescriber:
- Which medications will work most effectively
- Whether or not a medication will cause side effects
- What side effect a medication might cause
The testing can only tell an individual which medicines are more likely to cause trouble either by causing too many side effects, or not enough drug exposure. Ultimately, genetic testing will not fix an individual’s depression or anxiety by itself. Also, the testing does not always explain why an individual is having specific side effects.
Individuals can have different reactions to the same drug, even at the same dose, because they have different gene variants. The individual’s variant can affect the rate a medication moves through their body. Typically, the longer it takes your body to process a drug, the easier it is for the medication to have an effect. But in psychiatry, how fast an individual metabolizes a drug, and how well they respond to the drug, are sometimes not as strongly related.
As a prescriber, I order the testing with the intention to choose the most optimal medication for the patient. The testing is not an alternative intervention, it is additional information to consider. Many prescribers will decide to order the test if a patient does not respond to at least two antidepressants. Each psychiatric prescriber will utilize, or not utilize, the testing in their clinic, based upon their experience with its usefulness, or not, in their patient’s treatment plan.
There are never enough tools to help find the best treatment for an individual’s depression or anxiety. I believe if a test can help guide the prescriber to the best choice of medications, then it has helped put together another piece of the puzzle of psychiatry. Ultimately, the test results may help a provider make more informed decisions about choosing or managing patient’s medications. There are many tools one may use to help make the best clinical decisions for their patients. In my clinical opinion, the psychogenomic testing is one of the tools I find very valuable in my practice.