Have you heard of genetic-drug interaction testing for the selection of antidepressants? It’s billed as a simple blood test or cheek swab that can indicate what antidepressant you should or should not take. This is advertised as “personalized medicine” or “precision medicine.” And to anyone who has been on the (un)merry-go-round of antidepressant trials, it sure sounds like a great idea. Here’s the latest research on what you need to know about spending money on medical tests for antidepressant selection.
Genetic-Drug Interaction Testing for Antidepressant Selection — What Is Pharmacogenetic Testing?
Testing your genetic make up to determine how your body processes drugs is known as pharmacogenetic testing.
According to the American Academy of Child and Adolescent Psychiatry, pharmacogenetic testing can tell your doctor:
- How quickly you might process a medication
- How effectively you might process a medication
Pharmacogenetic testing can’t tell your doctor:
- Which medication will work most effectively for you
- Whether or not a medication will cause side effects
- What side effects a medication might cause
Pharmacogenetic Testing and Antidepressant Choice Testing
Running a couple of online searches on pharmacogenetic testing yields results primarily from companies trying to sell you just that. There’s big money to be had in testing when it comes to medication. And who doesn’t like the idea of personalized medicine? What would you pay to have to try only one drug as opposed to three or four or more? These factors often make this an easy sale.
And remember that pharmacogenetic testing is highly marketed in psychiatry to doctors just like it is to patients. The same types of promises are made to doctors as they are to patients, too. And if a doctor can help a patient with the first medication rather than the fifth, of course, they’re going to sign up.
But the question is, does genetic make up and drug interaction testing, pharmacogenetic testing, actually help people with mental illness?
Do Medical Tests for Antidepressant Selection Help People with Mental Illness?
This is the question that David Oslin, MD et al., set out to answer in the PRIME Care Randomized Clinical Trial. And in July, they published their findings with regard to major depressive disorder in “Effect of Pharmacogenomic Testing for Drug-Gene Interactions on Medication Selection and Remission of Symptoms in Major Depressive Disorder,” published in the Journal of the American Medical Association.
This was a pragmatic, randomized clinical trial that compared treatment guided by pharmacogenomic testing vs. usual care. Participants included 676 clinicians and 1944 patients. Initially, there seemed to be some increased remission in the pharmacogenetic testing group. However, at 24 weeks, there were no differences between the two groups.
In short, fancy, expensive, drug-gene interaction tests did not reveal a greater remission rate for those taking an antidepressant for major depressive disorder. (I wrote here about claims a blood test made that they couldn’t back up.)
Does Pharmacogenetic Testing Help Anyone? Should You Get an Antidepressant Genetic Test?
The above is about antidepressants for those with depression, so, of course, this can’t necessarily be generalized to all mental illness-kind; and pharmacogenetic testing is run with regard to illnesses outside of mental illnesses as well. I would say if you’re looking at pharmacogenetic testing for any illness, you should be skeptical and make sure there are actual benefits before you put your hard earned money on the line.
And when it comes to pharmacogenetic testing for those with mental illness, I’ll tell you what I’ve been telling people for a long time: If you have the money and you feel like spending it, go ahead and get the test. It likely won’t hurt you. However, if you don’t have the money, don’t fall victim to the marketing. It promises something it can’t deliver. We are in our infancy when it comes to understanding medication, mental illness, and the brain. Personalized medicine for mental illness is just a dream right now. I really hope we get to a place where a simple blood test or cheek swab will tell us what we need to know about treating mental illness, but that certainly isn’t the reality in which we live today.
Image by the University of Michigan.
I had the GeneSight test. At the time, my doctor had switched me from Lexapro to Zoloft. I suddenly became extremely depressed and suicidal. That’s when my doctor recommended the test. I found out that my body doesn’t metabolize Zoloft well, so I may as well have come off my antidepressant. Had we done the test sooner, we could have avoided that whole ordeal because my doctor would have known not to bother prescribing Zoloft.
The test also told me Tegretol can be potentially fatal to me, therefore it should not be prescribed. What if my doctor prescribed Tegretol not knowing this and I died?
I agree the test does not predict what medications will work, so they might be advertising it as doing more than it does, but it’s still valuable to have because it can help you avoid bad situations.