How the human body responds to the medications used to treat depression is very complicated.
First, there’s a lot we don’t know about depression. According to Harvard Health:
“Research suggests that depression doesn’t spring from simply having too much or too little of certain brain chemicals. Rather, there are many possible causes of depression, including faulty mood regulation by the brain, genetic vulnerability, stressful life events, medications, and medical problems.
With this level of complexity, you can see how two people might have similar symptoms of depression, but the problem on the inside, and therefore what treatments will work best, may be entirely different.”
Additionally, the body’s ability to respond to the medications is impacted by many factors such as drug/drug interactions, food/drug interactions, lifestyle factors, age, allergies – and your unique genetic code. The last factor is where the GeneSight test comes in.
The GeneSight test is a pharmacogenomic test that analyzes how your DNA may affect your response to depression medications. The GeneSight test can help inform your doctor about which medications may require dose adjustments, may be less likely to work, or may have an increased risk of side effects based on your genetic makeup.
However, the GeneSight test results are not meant to be the only source of information your doctor considers when selecting a new medication. The GeneSight test is intended to supplement other information considered by your healthcare provider as part of a comprehensive medical assessment.
Medication Response Factors
There are numerous other factors that may impact how a patient may respond to medications, including:
- Drug/drug interactions– a drug/drug interaction could potentially occur when you are taking multiple medications at the same time. One medication may impact how your body metabolizes another medication. According to Harvard Health, “a drug, supplement, or food may affect how long a medication stays in the body, often by stimulating or inhibiting the production of specific enzymes in the liver or intestine. These enzymes are part of the cytochrome p450 system, which plays an important role in metabolizing many medications.”
- Food/drug interactions– similarly, what you eat could impact how well you metabolize certain medications. “Some food products are fortified with vitamins and/or minerals that can interact with certain drugs,” states an article in U.S. Pharmacist. “There are hundreds of drug/nutrient interactions.” Some examples of nutrients and foods that can interact with medications are grapefruit juice, caffeine, protein-rich foods or high-fat meals.
- Lifestyle factors– smoking and other lifestyle factors can contribute to how your body metabolizes certain medications. For example, tobacco smoke “induces many of the CYP450 enzymes in the liver, which play an important role in medication absorption, distribution, metabolism, and elimination,” according to an article in Pharmacy Times. “Psychiatric medications such as antipsychotics, antidepressants, hypnotics, and anxiolytics are widely affected by cigarette smoking.”Mixing alcohol and psychotropic medication can have a detrimental impact. “Many medications can cause problems when taken with alcohol – including anti-anxiety medications, sleep medications and prescription pain medications. Side effects may worsen if you drink alcohol and take one of these drugs along with an antidepressant,” warns the Mayo Clinic. “When combined with certain types of alcoholic beverages and foods, antidepressants called monoamine oxidase inhibitors (MAOIs) can cause a dangerous spike in blood pressure.”
- Age– Your age is another factor that may impact outcomes with certain medications. The FDA states: “as you get older, body changes can affect the way medicines are absorbed and used. For example, changes in the digestive system can affect how fast medicines enter the bloodstream. Changes in body weight can influence the amount of medicine you need to take and how long it stays in your body. The circulatory system may slow down, which can affect how fast drugs get to the liver and kidneys. The liver and kidneys also may work more slowly, affecting the way a drug breaks down and is removed from the body.”
- Allergies– Allergic reactions to medication is another factor for your doctor to consider. The Mayo Clinic indicates that a “drug allergy is the abnormal reaction of your immune system to a medication… The most common signs and symptoms of drug allergy are hives, rash or fever. A drug allergy may cause serious reactions, including a life-threatening condition that affects multiple body systems (anaphylaxis)… a drug allergy is not the same as a drug side effect, a known possible reaction listed on a drug label.”
Considering a Patient’s Entire Clinical Profile
Both healthcare providers and patients should note that it is important to take into consideration a patient’s entire clinical profile for medication selection, including the factors listed above. It is also important to note that all medications come with their own risk of side effects. While genetics is able to provide some insight and guidance, it cannot tell us the “best” medication for a patient. The GeneSight test can help informmedication selection, but it cannot and should not be used as the only consideration in medication selection, as genetics is only one part of the puzzle.
This document is for educational purposes related to pharmacogenomics and personalized medicine only and should not be considered medical advice. The information is based on scientific opinion from industry experts and is intended to provide additional information to healthcare providers. These materials may be changed, improved, or updated without notice. Myriad Neuroscience is not responsible for any errors or omissions contained in third party content. We encourage you to contact us for specific scientific advice regarding our GeneSight® tests. You may print a copy of this document for your own personal noncommercial use. You may not copy any part of this document for any other purpose, and you may not modify any part of this document without the permission of Myriad Neuroscience. “GeneSight,” “Myriad Neuroscience” and associated logos are registered trademarks of Myriad Neuroscience. © 2019 Myriad Neuroscience. All rights reserved.