Pharmacogenomic Testing in Psychiatry: How Does It Work?
Two people take the same antidepressant at the same dose. One feels steadier within weeks. The other gets dizzy and nauseous and stops. Genes can be part of the reason. Pharmacogenomic (PGx) testing reads your genetic makeup to predict how you will process and respond to certain mental health medicines. That includes antidepressants, antipsychotics, mood stabilizers and ADHD treatments. It belongs to precision medicine: fitting the medicine to the person. This blog explains how it works and where it helps.
According to Dr. Prakhar Jain, Psychiatrist in Mumbai, “A gene report does not choose the medicine. It gives the doctor one more piece of information, to be read alongside your symptoms, your history and the other medicines you take.”
How Does Pharmacogenomic Testing Work?
You hand over a small sample. A cheek swab, or a little blood.
- Enzymes do the clearing: The liver clears medicines with help from enzymes. Two of them, CYP2D6 and CYP2C19, matter a lot in psychiatry. Your genes set their speed.
- Four metabolizer types: Labs report one of four: poor, intermediate, normal or ultrarapid. Poor metabolizers clear slowly. Drug levels build up, and side effects can follow. With fast clearance (ultrarapid metabolizers), the dose may not do much.
- Other factors count too: Genes are only part of it. Smoking matters. So does diet. Age, other medicines, and liver and kidney function too. A gene report can’t see them.
- It reads inherited DNA only: The test does not diagnose a mental health condition. It shows how you may handle certain medicines.
For how testing is arranged in practice, see the pharmacogenomic testing page.
What Is Pharmacogenetic Testing Used For in Psychiatry?
Mainly for medicine choice and dosing. Here is where it comes up.
|
Medicine group |
Why genes matter |
Example from the research |
|
Antidepressants |
The enzymes set how fast they clear |
Slow enzymes: some tricyclics may need a lower first dose |
|
Antipsychotics |
The enzymes affect how long they stay |
Slow enzymes: aripiprazole levels run higher |
|
ADHD medicines |
CYP2D6 handles atomoxetine |
Slow enzyme: about ten times more of the drug in the body |
|
Mood stabilizers |
Depends on the drug |
Carbamazepine: people of Asian ancestry get a gene check (HLA-B*1502) first. Lithium: not guided by genes |
- When testing is considered: Usually after a medicine caused trouble or did nothing. After several such tries, testing makes more sense. No guideline yet asks for everyone to be tested.
- What the research shows: A 2025 review looked at 18 articles. Nine were trials, nine were meta-analyses. At 8 and 12 weeks, response and remission were better with gene-guided care. By six months, the gain looked smaller.
- Where the evidence is thin: Many trials were not blinded. Some had industry funding. Most volunteers were of European ancestry. One guideline rated the evidence low.
- What it cannot do: No test can promise which medicine will work. Many drugs have no gene guidance. It adds one piece to a clinical assessment.
When several medicines have not worked, other options exist. The post on how TMS therapy works for depression covers one.
Why Is Pharmacogenomic Research Done, and What Does a Test Cost?
Research here has one aim: less guesswork. The report usually ends in one of four suggestions.
- Why the research exists: Researchers want to know how genes affect drug response. A better first match is the hope. Less guessing.
- Genetic or genomic: The two words get mixed up. Genetic usually means one gene. Genomic covers many genes at once, even the whole genome.
- What a test costs: Prices are not standard. Labs differ. So does the number of genes tested. A doctor’s review may be billed separately. Ask for the full amount itemised, in writing.
- Privacy and consent: Ask where your DNA data is stored and who can open it. How long is it kept?
Low mood that medicines haven’t fixed? The depression treatment page shows how a doctor reviews options.
Key Takeaways: PGx testing reads inherited DNA. It hints at how you may handle some mental health medicines. Doctors may use the result to set a dose or choose another drug, usually after trouble with a medicine. The evidence is limited. Early results are encouraging. No test predicts everything. Get the price in writing. A psychiatrist can say if it suits you.
Want to know whether gene-based testing could help guide your medicine choices?
FAQs
What is pharmacogenetic testing used for in psychiatry?
Doctors use it when a medicine fails or causes side effects.
How does pharmacogenomic testing work?
You give a cheek swab or blood sample. A lab reads the genes.
How much does a pharmacogenetic test cost?
No single price. It varies by lab, gene panel and what’s included.
What is the purpose of pharmacogenomic research?
To see how genes change drug response, so prescribing fits the patient.
Reference
Disclaimer: This blog is for educational and informational purposes only and should not be considered professional advice.
MBBS, M.D. (PSYCHIATRY), PDF, EMH (USA)
Child & Neuro Psychiatrist.
Dr. Prakhar Jain is a Psychiatrist in Mumbai, and has an experience of more than 13 years in this field. Dr. Prakhar Jain practices at Breach Candy Hospital, Bombay Hospital & Grace Medical Centre in Mumbai. He completed MBBS from Indira Gandhi Government Medical College, Nagpur and M.D. (Psychiatry) from Grant Medical College and Sir JJ Hospital, Mumbai.
Several anxiety disorders commonly occur independently of depression.