Pharmacogenomic (PGx) testing is emerging as a promising tool in mental health care, using genetic insights to tailor antidepressant and antipsychotic treatments. PGx testing is a precision (also called personalized) medicine technology that examines genetic variation in the way medication is metabolized or broken down for processing by the body.
By analyzing an individual’s unique genetic profile, this testing aims to tailor personalized treatment strategies that improve therapeutic outcomes, optimize the medication selection process, and enhance patient experiences. The goal is to reduce the trial-and-error approach to prescribing. Read on to learn more about this emerging field.
Genetic Testing for Mental Health
Although many people with psychiatric disorders can manage their symptoms with various medicines, it can be challenging to find the most appropriate treatment for each patient due to the wide array of available drugs and the large variability in response between individuals.
For example, studies show that a clinically significant response is not reached with initial antidepressant medication in as many as 50% of people with major depressive disorder.
Pharmacogenomics, which is the study of how genes affect a person’s response to particular drugs, is one of the core elements of precision medicine. PGx tests for psychiatric disorders that are available in the US include direct-to-consumer tests and tests that are offered as a laboratory service. These tests are quite different, including the types and number of genes examined, cost of testing, and methods used for sample collection and analysis.
PGx testing has been available for about 20 years and numerous recommendations exist regarding the types of PGx information that should be used to guide prescribing decisions. Nonetheless, this form of testing has yet to be integrated into most psychiatric care practices in the US and worldwide [1].
Key Benefits of PGx Testing
PGx testing has the potential to benefit a wide variety of people who are starting a new medicine treatment for mental health disorders, including people:
- With treatment-resistant conditions
- With a family history of poor response to specific medications
- Who are using multiple medications and may be at risk for drug-drug interactions
- Who have experienced serious treatment related side effects in the past
Some of the main benefits are as follows:
Improved Treatment Outcomes
- One trial showed an 89% higher remission rate in treatment-resistant depression when PGx-guided treatment was used compared to standard care [2].
- In a randomized study, patients using PGx testing (e.g., Pillcheck’s service) experienced twice the improvement in depression and anxiety symptoms over six months [3].
- The GUIDED trial found PGx-guided medication changes led to greater symptom reduction and remission in major depressive disorder [4].
- PGx testing has been shown to provide an increased chance of achieving a therapeutic outcome among youth with depression [5].
Cost-Effectiveness
- It has been estimated that pharmacogenomic testing can contribute to reducing healthcare costs by decreasing:
- Adverse drug reactions
- The number of drug switches and recurrent dose adjustments
- The time until disease remission
- Disease burden and related costs.
- A 2023 analysis projected $956 million in savings for the U.S. healthcare system by avoiding ineffective treatments and hospitalizations, equating to ~$5,000 per patient [4].
Reduced Side Effects
- PGx testing has been linked to 21% fewer adverse drug reactions in some studies, particularly for medications metabolized by high-risk genes like CYP2D6 [2].
Current Applications
Genes and Biomarkers
- Testing focuses on polymorphisms (variations in DNA sequences) affecting drug metabolism (e.g., CYP2D6 for SSRIs, HLA-B for carbamazepine hypersensitivity), and neurotransmitter activity (e.g., HTR2A for serotonin receptor drugs).
- Guidelines from CPIC and DPWG provide actionable recommendations for dosing adjustments based on genetic results [4].
Real-World Programs
- Pillcheck: Combines DNA analysis with pharmacist reviews to recommend alternatives for poorly tolerated antidepressants [3].
- Mayo Clinic’s Pilot: A mental health-focused program saw 80% symptom improvement in patients whose medications were adjusted post-PGx testing.
Challenges and Limitations
Uncertain Evidence and Inconsistent Guidelines
- Although some studies suggest PGx testing provides benefits over treatment as usual, the evidence is often conflicting and of limited quality. Various technical concerns do not allow a clear and consistent interpretation of the results [1].
- While some trials show significant benefits, others highlight inconsistencies due to small sample sizes, variable testing panels, and heterogeneous study designs.
Implementation Barriers
- Limited clinician awareness, out-of-pocket costs for tests (ranging from $200–$2,000), and lack of standardized protocols hinder widespread adoption [2].
Ethnic and Racial Gaps
- Most genetic data derive from populations of European ancestry, raising concerns about generalizability.
Privacy and Confidentiality Concerns
- PGx testing involves the collection and storage of massive amounts of sensitive health data, and the privacy and security of this data are essential. Ensuring conformance to data collection, storage, and privacy is critical.
Future Directions
PGx testing is not yet routine in psychiatry, but its integration into population health programs and electronic health records could streamline personalized care. Ongoing research aims to validate biomarkers for bipolar disorder and schizophrenia, expand diverse genomic datasets, and refine cost-benefit models [4].
While challenges persist, PGx testing represents a critical step toward precision psychiatry, offering hope for patients with treatment-resistant conditions.
Improving Mental Health in Utah
Treatment for mental health conditions is available in Utah. Are you or a loved one looking for a compassionate space to heal from anxiety, trauma, PTSD, other mental health conditions, or addictions? Our licensed trauma-informed professional therapists and counselors at Corner Canyon Health Centers can provide compassionate help using a range of therapeutic and holistic techniques.
Reach out to our Admissions team now at Corner Canyon. We’re in a peaceful setting bordered by the beautiful Wasatch Mountains.
Sources
[1] Young, C. and D. MacDougall. 2023. CADTH Horizon Scan. An Overview of Pharmacogenomic Testing for Psychiatric Disorders. Canadian Journal of Health Technologies. June 2023 Volume 3 Issue 6.
[2] CAMH. 2022. Pharmacogenetic testing shows promise improving symptoms in patients with treatment-resistant depression.
[3] Litinski V. Personalized medicine: Improved mental health treatment guided by DNA. Pillcheck.ca
[4] Munz K. 2024. Need for Pharmacogenomic Testing in Mental Health Care Explored at AMCP 2024.
[5] Roberts B, et al. 2023. Utility of pharmacogenetic testing to optimise antidepressant pharmacotherapy in youth: a narrative literature review. Front Pharmacol. 2023 Sep 19;14
