Pharmacogenetic Testing (Genetic Testing for Psychiatric Medications)

Pharmacogenetic testing, also called genetic testing for medications, genetic testing for antidepressants or PGx testing, looks at how your genes may affect the way your body processes certain medications. The results can inform dosing for some medications and flag medications that may need extra care, but how you respond to a medication is still individual and can’t be predicted by the test. At ANK Behavioral Health, it’s ordered when your provider thinks it would be helpful.

Most visits are by secure video, anywhere in New Jersey. Our office is in Mount Laurel, NJ, and in-person visits there are limited and by appointment only; ask our office.

What Is Pharmacogenetic Testing?

Pharmacogenetic testing looks at your genes to see how your body might handle certain medications.

Genes carry information that controls how your body works, and some also affect how your body uses and breaks down medications. Those differences can change how much of a medication stays in your body, which is one of many factors in how it works for you and whether it causes side effects.

The test can be done on blood, saliva or cells swabbed from your cheek. Your provider will explain how the sample is collected. It’s often a quick cheek swab.

How It Works

Once your sample is collected, a lab looks at specific genes. Some of these genes influence how the body breaks down many common antidepressants.

The results usually sort you into groups like:

• Fast processor (rapid or ultrarapid metabolizer): your body may break down some medications more quickly
• Slow processor (intermediate or poor metabolizer): your body may break down some medications more slowly, so levels may run higher
• Typical processor (normal metabolizer): your body breaks down the medication at the expected rate

This tells you about how your body processes a medication. It doesn’t tell you how well that medication will treat your symptoms.

What the Test Can Tell You

Pharmacogenetic testing can offer helpful information. It may:

• Show how your body may process some medications
• Help inform dosing for some medications
• Flag medications your body may process differently, which can be one factor in side effects
• Give your provider one more piece of information to use along with everything else about your condition

For some medications, results can help inform dosing or point out medications that may need extra care. How you respond is still individual.

If your results show no expected gene interactions, that’s useful information too. It suggests that how your body processes these medications is less likely to explain past problems. It doesn’t rule that out completely, because rare gene variants and other things, such as age, diet or other medications, can also affect how your body processes a medication. Your provider then looks more closely at other factors, such as the diagnosis, whether medications were tried at an adequate dose and for long enough, other medications, sleep, alcohol or other substances, stress, and whether therapy is part of the plan. We don’t offer standalone weekly therapy, but we’re happy to help you find a therapist and, with your permission, we’ll coordinate with them.

What the Test Cannot Tell You

It’s just as important to know the limits. Pharmacogenetic testing is a guide, not a guarantee. It cannot:

• Tell you which medication will work
• Diagnose a condition or tell you your risk of developing one
• Replace a careful evaluation
• Predict how you’ll respond or every side effect
• Make decisions for you or your provider

Your symptoms, history, and goals still matter most. The test adds information—it doesn’t take the place of good care.

What the Research Does and Doesn’t Show

Pharmacogenetic testing for antidepressants is debated among researchers. Part of the science is well established. Whether testing helps people get better is much less settled, and it helps to know which is which.

Well supported: genes can change how some medications are processed. The FDA’s table of gene and medication associations lists some psychiatric medications where the data support specific prescribing advice, such as citalopram with the CYP2C19 gene and carbamazepine with a gene variant called HLA-B*15:02. The Clinical Pharmacogenetics Implementation Consortium (CPIC), a nonprofit group, has guidelines for using CYP2D6, CYP2C19 and CYP2B6 results to help inform prescribing of SSRIs, SNRIs and similar antidepressants, and for CYP2D6 and CYP2C19 with older tricyclic antidepressants. The same SSRI and SNRI guideline says the data for two other genes, SLC6A4 and HTR2A, don’t support using them to prescribe these medications. One limit: as the 2022 VA/DoD depression guideline points out, CPIC’s recommendations so far aren’t based on clinical outcomes, meaning studies of whether patients actually do better.

Mixed: the two large U.S. trials. The GUIDED trial (2019) followed 1,167 people whose depression hadn’t responded well to at least one antidepressant. On its main measure, symptom improvement at 8 weeks, there was no clear difference: 27.2% with test-guided care and 24.4% with usual care. Two other measures did favor testing: response, meaning symptoms at least cut in half (26.0% versus 19.9%), and remission, meaning few or no symptoms (15.3% versus 10.1%). The trial’s sponsor was the company behind the test.

The PRIME Care trial (2022), funded by the U.S. Department of Veterans Affairs, included 1,944 patients at 22 VA medical centers. Test results did change prescribing: 59.3% of patients in the testing group received a medication with no predicted gene interaction, compared with 25.7% in usual care. Remission was slightly more common over the 24 weeks (a difference of 2.8 percentage points), but the difference at week 24 itself wasn’t statistically significant. The authors described the effects on remission as small and not lasting.

Debated: what the pooled studies mean. Reviews that combine many trials tend to find a modest benefit, with real caveats. A 2024 meta-analysis of 15 trials found symptoms fell by an average of 31.0% with testing and 26.8% without, but most of the benefits lost statistical significance when only the studies at low risk of bias were counted, and it found no advantage in how well people tolerated treatment. A review of 12 randomized trials called the results promising, noted less favorable remission results in recent studies, and advised caution. A 2026 review of 8 randomized trials found that results weren’t consistent across tests, so research on one test may not apply to another.

What U.S. groups say. A 2024 American Psychiatric Association workgroup review concluded that the evidence doesn’t support using currently available multigene panels to choose treatment for major depression, and noted that none of the trials it reviewed was fully blinded. The VA/DoD guideline found insufficient evidence to recommend for or against testing; it came out before PRIME Care was published. The trials above studied depression, so they say little about other conditions.

The FDA’s caution. In 2018, the FDA warned about pharmacogenetic tests with unapproved claims to predict a person’s response to a specific medication. In 2019, it said again that patients and health care professionals shouldn’t rely on tests making claims that haven’t been established and aren’t described in the drug labeling. Its table adds that genes are only one of many factors in how a medication works, and that most of the listed associations haven’t been studied for whether testing improves clinical outcomes.

Taken together, the research supports what we tell patients: the test can add useful information, but it’s a guide, not a guarantee. Please don’t change a medication based on results alone; talk with your provider first. Please don’t stop a medication on your own; some can cause withdrawal symptoms or a return of symptoms if stopped suddenly.

Who Might Benefit

Pharmacogenetic testing isn’t right for everyone, and it isn’t routinely needed before starting a medication. Neither the VA/DoD guideline nor the 2024 American Psychiatric Association workgroup review recommends it for choosing treatment. It may be most informative if:

• You’ve tried several medications without enough improvement
• You’ve had strong side effects from medications

The evidence for this is limited. The GUIDED trial studied people whose depression hadn’t responded well to at least one antidepressant, and PRIME Care included people starting or switching treatment. A review of trials in treatment-resistant depression found a small benefit, based on low-quality evidence, and no clear difference in side effects. An earlier American Psychiatric Association workgroup review said testing may be informative in some situations, particularly in predicting side effects.

We’ll talk through whether testing makes sense for you. Not sure if testing is for you? Start with our short guide.

How We Use It at ANK Behavioral Health

We don’t order tests just because they exist. If your provider recommends testing, they’ll explain why, what it can show, and how they’ll use the results.

Pharmacogenetic tests are offered by several companies. They differ in which genes they include and how they turn results into medication guidance, and research on one test may not apply to another. At ANK, pharmacogenetic testing is ordered by your provider as part of a visit when they think it would be helpful. Not every provider offers it, so ask the provider you’re seeing whether it’s an option for you. If you’ve already had a pharmacogenetic test elsewhere, bring your results to your visit.

What to Expect

If testing is part of your plan, here’s what usually happens:

1. We talk it through. We explain the test and answer your questions first.
2. You give a sample. Often a quick cheek swab.
3. The lab does its work. Results can take from a few days to a few weeks.
4. We review it together. We walk through what the results mean for you.

The goal is always the same: a treatment plan that fits your life.

A Tool, Not the Whole Answer

Pharmacogenetic testing can add useful information. But it’s one part of a bigger picture.

Good care still comes down to time, listening, and a plan built around you. Testing can support that process. It doesn’t replace it.

Sources

The FAQ below also draws on these sources:

• MedlinePlus: Pharmacogenetic Tests
• MedlinePlus Genetics: Cost of genetic testing and how long results take
• FDA: Table of Pharmacogenetic Associations
• CPIC guideline for serotonin reuptake inhibitor antidepressants (2023)
• VA/DoD guideline for major depressive disorder (2022)
• American Psychiatric Association workgroup review (2024)
• U.S. insurer coverage policies for pharmacogenomic testing in psychiatry (2025)

Ready to Take the Next Step?

If you’ve tried medications that haven’t helped enough, or have had strong side effects, we’ll help you understand your options, including whether pharmacogenetic testing is worth considering.

Start your intake packet to begin with a thorough evaluation and a plan that fits you. Once it’s submitted, we’ll verify your insurance and call you to schedule your appointment.