Pharmacogenomics and Drug Prescribing (Genetically Guided Prescribing) in Psychiatry – The Current State of Evidence
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]
- 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]
Hicks, J. K., Bishop, J. R., Sangkuhl, K., Müller, D. J., Ji, Y., Leckband, S. G., … & Gaedigk, A. (2015). Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline for CYP2D6 and CYP2C19 genotypes and dosing of selective serotonin reuptake inhibitors. Clinical Pharmacology & Therapeutics, 98(2), 127-134.
van Westrhenen, R., van Schaik, R. H. N., Van Gelder, T., Birkenhager, T. K., Bakker, P. R., Houwink, E. J. F., … & van Weelden-Hulshof, M. J. M. (2021). Policy and Practice Review: A First Guideline on the Use of Pharmacogenetics in Clinical Psychiatric Practice. Frontiers in pharmacology, 12, 187.
Eap, C. B., Gründer, G., Baumann, P., Ansermot, N., Conca, A., Corruble, E., … & Hiemke, C. (2021). Tools for optimising pharmacotherapy in psychiatry (therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests): focus on antidepressants. The World Journal of Biological Psychiatry, 1-68.