Genetic testing for choosing the right medication for your child. Does it actually work?

A question that I see coming up a lot on the Facebook mom forums concerns the usefulness of genetic testing for their children.  Moms would like to know if genetic tests can tell them if their child is going to do well on a medication without having to try it for 2-3 months.

There is some confusion about what these tests can actually do.

These tests work by looking at your child’s genetic material.  Their genetic material is essentially the instruction book of what makes them who they are. The test predicts how well their body is  going to play with the medication.

These genetic tests do not predict whether or not the medication is going to improve your child’s symptoms. Instead, these tests tell us whether or not the medication is going to cause side effects, like a terrible stomach ache or turn them into a zombie. 

How does it work?

You provide a testing company, like GeneSight, your child’s cheek swab sample.  This sample contains tiny pieces of their genetic material.  Back in the lab they study the genetic material and predict how well your child’s body would metabolize (process and break down) each medication on their list.

They then create a report for you. The report has three columns; green, yellow and red. In the accompanying PDF for this post I have provided an example of what the medication report looks like.

Medications in the green column should not cause any side effects. 

Medications in the yellow column suggest a ‘moderate’ interaction between your child’s body and the medication, meaning they might have some mild to moderate side effects. 

Medications in the red column do not play nicely with your child’s body. It suggests that their body would break down and remove this medication slowly. This means that the medication stays active for longer in their body. This can cause levels of the medication to build up, causing side effects.

In this weeks handout here, I have provided an example of what this color coding looks like on an actual medication report

Does this mean you shouldn't use medications in either the yellow or red columns? Should you only use medications in the green column?

No. Medications in the yellow and red columns might be incredibly helpful at helping control your child's symptoms.  Your healthcare provider might just have to give you lower doses of those medications to make sure they don't build up to levels in their body that cause unpleasant side effects. 

Medications in the green column will be less likely to cause side effects, but that doesn't mean that they will help your child feel better.  They may be green and not be the right medication for your child.

But is there a way to test whether or not a medication will actually help my child?

In short, no.  Whether or not the medication works in helping with your child’s symptoms cannot be tested unfortunately.  These tests only tell us if they will have side effects.  

For example, your child could be on an antidepressant that does not give them any side effects, but also doesn't really work to lessen their depressive symptoms.  Just because they are not throwing their guts up on that particular medication does not make it a useful medication for you, or them. 

On the other hand, you could have an antidepressant that causes a lot of side effects, but works really well to help lessen their depression. Despite the fact it works so well, your child is likely going to stop that medication pretty quickly because they are having a miserable time and it’s not worth the trade off.

What I’ve seen in the clinic

In my own experience what I'm seeing is that these genetic test results do accurately tell me whether or not an individual is going to have side effects. 

But how do I know, for real?

So, before a person comes into the clinic they have likely already tried and tested a handful of medications over the years.  Nine times out of ten, the medications that caused them the most issues are in the red column, with a few sprinkled in the yellow column. The medications in the green column did not give them nasty side effects in the past.

Again, this does not mean that those medications in the green 'cured' their symptoms.  It means that they just weren't suffering any side effects. 

The report confirms what the person experienced themselves; medications in the yellow and red made them feel lousy due to side effects.  

How much does it cost?

I will give GeneSight as an example. It is not covered by commercial insurances. You will have to pay out of pocket. It costs a few hundred dollars based on income level.  If it ends up costing more than $330, the company will contact you first to let you know before running the test so that you can pull out if you want. 

In the accompanying hand out here I have provided an example of the financial information sheet for GeneSight which was accurate as of December 2023.

Do you recommend genetic testing for helping to choose medication?

Genetic testing is a useful tool in that it provides us with a piece of the puzzle.  It lets us know whether or not your child is going to have an awful time with side effects on a medication. 

Genetic testing takes out some of the guesswork and definitely saves time. Your child is not suffering for weeks on end with a medication that was always destined to cause troublesome side effects for them.

What it does not tell us is whether or not they will get better on the medication.  Unfortunately we still don't have any test for that. 

But what we do have is your family history.  If either you, your partner or another biological family member has had good improvements in symptoms with a medication in the past, it is likely that your child will also respond well. It is definitely worth trying out that medication that has a good track record with your family's genetics!

This site is for general informational purposes only and does not constitute the giving of medical advice. The contents do not constitute the practice of medicine, nursing, or other professional health care services. No provider–patient relationship is formed.