Pharmacogenomics and Drug Prescribing (Genetically Guided Prescribing) in Psychiatry – The Current State of Evidence

Posted on:July 25, 2021
Last Updated: August 1, 2021
Time to read: 10–12 minutes

Pharmacogenetics and pharmacogenomics describe the study of genetic variations that can be used to inform and predict an individual’s response to drugs. [Weinshilboum and Wang 2006], [Hicks 2015]

In psychiatry, the identification of genes associated with an individual’s response to pharmacotherapeutic drugs is designed to inform personalised treatments and improve treatment outcomes. [Singh et al 2014], [Polasek et al 2019]

The evidence has matured to a level where guidelines for implementation have emerged. [Hicks et al 2015], [Sebastian et al 2021], [van Westrhenen et al 2021]

  • Pharmacogenetics is generally used for identifying specific genes that influence the absorption, distribution, metabolism, and excretion (ADME) of medications. Genetically guided prescribing to reduce trial and error is the aim.
  • Pharmacogenomics evaluates how variations in an individual’s genetic profile interact with environmental determinants such as diet, microbiome, age, lifestyle, and physical health.
  • It is more an explorative entire multi-omic approach rather than being of more immediate translatable utility. Examples would be exploring genomic polygene pathways to elucidate the pathophysiology of psychiatric illnesses or identify novel classes of medication action.

After completing the Human Genome Project, it was expected that pharmacogenetics and the knowledge of a patient’s genetic signature would enable predictions of psychiatric treatment response and treatment-related adverse effects. However, the integration of genomic data has been challenging due to the complexity of how multiple genes interact with environmental factors, which then determine response. [1000 Genomes Project Consortium et al. 2015]