Pharmacogenomics, or the study of how genetics affect your body’s response to medications, is a relatively new and exciting field of science. Scientists are learning more each day about how genetic testing can be used to select the best medication for patients. Genetic testing can help a doctor determine whether a medication will be effective for a patient and provide dosing guidance. It can also help alert clincians to medications that might be potentially harmful to patients.

Genetic testing has become increasingly popular among doctors who prescribe psychiatric medication, in particular antidepressants. Finding the right mental health medication can sometimes be a slow process full of unpleasant side effects. Roughly 40% of people who take an antidepressant will stop taking the medication within the first three months because of side effects or because they believe the medication is ineffective. People who take antidepressants often complain of unpleasant side effects like nausea, sexual dysfunction, headaches, drowsiness, dry mouth, and increased anxiety. When a person experiences side effects, it is easy for them to become discouraged and assume that no medication will help their condition.

Medication Side Effects

Side effects sometimes occur because people metabolize medications differently depending on their genetic code. For example, some people might metabolize an antidepressant more slowly, and a higher concentration of the medication in their body can cause unpleasant side effects. People who metabolize a medication very quickly might have fewer side effects but might need more of the medication to effectively treat depressive symptoms. Therefore, doctors are increasingly recommending genetic testing for depression medications to find the proper dosage and the right medication which may result in fewer side effects.

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How Does Genetic Testing Work?

Genetic testing is designed to be easy and painless. To complete the test, a laboratory collects a small sample of blood or saliva from the patient. The sample is usually sent to a pharmacogenomic testing laboratory to be analyzed. This lab sequences the DNA and analyzes any variations or changes in specific genes that are associated with how you respond to a particular medication. Testing for a specific kind of medication only has to be done once, but you may require additional pharmacogenomic testing if your doctor wants to evaluate you for another type of medication.

Psychiatric Medications Available for Testing

Because the field is still in its infancy, there is not pharmacogenomic testing available for every medication. But genetic testing is available for many of the medications that treat psychiatric conditions including anxiety, depression, bipolar disorder, schizophrenia, panic disorder, obsessive compulsive disorder (OCD), and post-traumatic stress disorder (PTSD). Here are just a few of the many psychiatric medications currently available for testing:

  • alprazolam (Xanax)
  • aripiprazole (Abilify)
  • brexpiprazole (Rexulti)
  • bupropion (Wellbutrin)
  • citalopram (Celexa)
  • clonazepam (Klonopin)
  • duloxetine (Cymbalta)
  • escitalopram (Lexapro)
  • fluoxetine (Prozac)
  • fluvoxamine (Luvox)
  • lorazepam (Ativan)
  • paroxetine (Paxil)
  • quetiapine (Seroquel)
  • risperidone (Risperdal)
  • sertraline (Zoloft)
  • venlafaxine (Effexor)

It is important to note that genetic testing is not always completely accurate. Because the field is still new, there are only a few studies supporting the claim that patients who undergo genetic testing for medication will have more positive outcomes than patients who do not. There also are limitations to what genetic testing can tell you about how your body will metabolize a medication. There is not one pharmacogenomic test that will provide information about all medications so you may need more than one test if you are taking more multiple meds. And, some medications can’t be tested using this method (i.e. aspirin and other over-the-counter pain relievers).

Sometimes genes have a strong influence over how the medication works, and sometimes other factors are more influential. These factors can include gender, age, nutrition, smoking history, and pregnancy. Your other medical conditions and any medications you take—both prescription and over-the-counter—can also affect how medications are metabolized. Your doctor may take all of these factors into consideration when they prescribe you a medication and when they consider whether to recommend that you complete genetic testing.

Insurance Coverage for Genetic Testing

Insurance coverage for genetic testing may vary depending on your insurance plan and personal history. You or your doctor may be required to submit documentation proving that you have a certain diagnosis or have experienced difficulty finding the right medication. It may be helpful to ask your healthcare provider for the specific procedure and medical billing codes for the lab tests they’d like to order before calling your insurance company about coverage. If your insurance doesn’t cover the cost, check with the genetic testing company to see if they offer any payment assistance—these tests can cost a few hundred dollars.

Treating mental illness usually involves a combination of medication, psychotherapy, and psychoeducation. So it’s important to participate in other kinds of treatment and self-care activities while taking medication. Your diet, sleep, exercise, and other factors can also play a role in your mood and how your body responds to medication. As your body ages and develops, you may also find that medications will need to be adjusted by your doctor.

How to Talk to Your Doctor about Finding the Right Medication

Talk to your doctor about whether genetic testing could be useful for helping you find the right medication. Patients who are in crisis or who have a history of difficulty in finding the right medication are sometimes more likely to be recommended for genetic testing. Your primary care doctor may also have to refer you to a psychiatrist to provide more specialized knowledge in selecting a medication or to evaluate whether genetic testing could be beneficial.

To prepare for your appointment, you may want to prepare notes about the following information:

  • Medications you’re currently taking (including over-the-counter and supplements)
  • Medications taken in the past and any side effects
  • Family history of mental illness and responsiveness to medications
  • Symptoms currently experienced
  • Diet and nutrition information including recent weight loss or weight gain
  • History of tobacco, alcohol, and drug use

Genetic testing isn’t a magic solution to a person’s mental health challenges, but it can sometimes provide your doctor with important information about how your body will metabolize certain medications. Many people, however, find the right medication for their symptoms without the use of genetic testing. So don’t be discouraged if it is not an option or not covered by your insurance. It never hurts, however, to start a conversation with your doctor about your options. The testing may not inform him of the perfect medication, but it can alert a physician as to what medications are likely to cause adverse effects or be ineffective. So don’t hesitate to talk to your healthcare provider about whether you might benefit from pharmacogenomic testing.

Last Updated: Jul 31, 2018