Treatment Resistant Depression: What Is It? - Myogenes

Treatment Resistant Depression: What Is It?

Aug 23, 2022

According to the World Health Organisation, depression is the leading cause of disability in the world. According to estimates from the NHS, 264 million people worldwide suffer from depression, and 1 in 4 people in England will experience some form of mental health problem each year.

Treatment for depression has evolved greatly over the years. With options such as therapy and medication(s), the symptoms of depression can be managed. However, some treatments may not be as effective as we would like them to be.

You may have treatment-resistant depression (TRD) when your symptoms of depression persist despite treatment. Learn about the warning signs of TRD, and how to manage your symptoms with treatment.

What Is Depression?

Depression is a mood disorder that negatively affects the way you feel, making it difficult to function throughout the day. Depression includes a variety of disorders such as bipolar disorder, postpartum depression, and seasonal affective disorder, but its symptoms are similar across all of them. Depressive symptoms can include:


  • Feeling low or down
  • An increase or decrease in appetite
  • You no longer feel joy from the things you used to enjoy
  • An overwhelming sense of fatigue
  • Having difficulty getting up in the morning
  • Suicidal thoughts or thoughts of self-harm

How to treat depression

If you are suffering from depression, your healthcare provider may recommend several standard tests and blood work to rule out other conditions in order to appropriately treat you. In addition, you might be referred to a psychiatrist or psychologist. You can discuss medication options with both your primary care provider and psychiatrist. In addition, psychiatrists and psychologists can provide counselling.

In addition to other treatments, your care provider may prescribe an antidepressant. Some examples of commonly prescribed antidepressants are sertraline and escitalopram.

For some, the medication may cause side effects, or may not alleviate symptoms. For others, symptoms may be reduced temporarily, but return shortly afterwards. This is called chronic or recurrent depression.

Treatment Resistant Depression 3

Treatment-resistant depression: How it Happens

Eventually, depression may become treatment-resistant if standard treatments fail. According to a study published in Patient Preference and Adherence, 10-30% of patients who suffer from depression show partial or no improvement after treatment. Some of the factors that can contribute to TRD include:


  • Medication adherence, or whether you take it according to prescription
  • Age
  • Misdiagnosis
  • Genetic factors

Drug-Gene Interactions

Depression treatment can be affected by certain genes. According to a study published in the Journal of Psychiatry & Neuroscience, genetic variances in the serotonin transporter-serotonin receptor system can impact the body’s response to SSRIs. The probability of response to TRD can be affected by these genes.

Researchers found that variations in the gene CYP2D6 can affect how antidepressants are metabolised. In some cases, the body may have too little or too much to combat depression symptoms.

Lastly, a study published in The International Journal of Neuropsychopharmacology found that GRIK4, BDNF, SLC6A4, and KCNK2 variations might also contribute to treatment-resistant depression.

Your genetic profile affects how your body processes or responds to medications, and not all medications will work the same for everyone.

Drug-Drug Interactions

Depression treatment can also be affected by medications prescribed to treat pre-existing conditions. If depression medication is taken with other prescriptions, whether for physical or mental health reasons, interactions may occur. In some cases, side effects of the two medications may overlap, while in others, one drug may interfere with the metabolism of the other.

Drug-drug interactions can lead to lower or higher levels of the drug in the body than expected. Before starting a new medication for depression, it is crucial to learn more about how they may interact.

How to Deal with Depression That Is Resistant to Treatment

Having depression that’s “treatment-resistant” doesn’t mean it can’t be treated.

It refers to depression that has not responded to two, three, or more medications and may require exploring other options. A different medication, a different dose, or a combination of medication(s) and other options may be needed. Consult your primary healthcare provider if your symptoms do not improve with your currently prescribed medication.

Pharmacogenetics should be considered

A pharmacogenetic test (PGx) examines the gene variants that may affect the effectiveness and tolerability of medications prescribed to treat your depression. The testing of genetic assays is often performed on patients who have experienced treatment resistance, and some research suggests that these individuals are best suited to receive this test.

Myogene’s pharmacogenetic test looks at 24 genes related to mental health treatment, including treatment options for TRD. It provides guidance across 10+ mental health conditions and 130+ medications to help clinicians determine:

  • Which medications are more likely to be effective
  • Which medications may be more likely to cause side effects
  • Personalised dosing guidance based on your metabolisation of medications

The Myogenes PGx test is a simple saliva swab test and can be done at a clinician’s office, or from the comfort of your home.

Pharmacogenomics Explained

Is Your Treatment Working for You?

It is possible to develop a more personalised treatment plan for depression with genetic testing. PGx testing is only one component of the treatment puzzle, but it is a very important one. Clinicians can better determine which medications are most appropriate for your genotype.

At Myogenes our experts have spent years formulating a series of tests which offer you real insights relating to your health such as The Pharmacogenetic Test, The Psychiatric Pharmacogenetic Test, The Hereditary Cancer Test, The Cardiology Test, and The Health & Wellbeing Test.


To speak to one of our advisors today, call us on 020 837 1266 or email