PSYCH 021: Pharmacogenetics

Why does one patient respond well to a medication while another experiences no benefit - or significant side effects? Pharmacogenetics seeks to answer this question by examining how genetic variation influences drug metabolism, efficacy, and tolerability.In this episode, we explore how differences in genes encoding drug-metabolising enzymes, receptors, and transporters can alter how medications are processed and how they act within the brain. Variations in systems such as cytochrome P450 enzymes can determine whether a drug is broken down too quickly, too slowly, or unpredictably.We examine how these differences translate into clinical outcomes - affecting dosing, response rates, and risk of adverse effects. This introduces the possibility of more personalised prescribing, moving away from trial-and-error approaches.However, pharmacogenetics also comes with limitations. Genetic factors are only one part of the picture; environment, comorbidity, and psychological context also shape treatment response. The promise of precision must therefore be balanced with clinical judgement.This chapter reframes prescribing as an interpretive process - where biology informs decisions, but does not dictate them. It offers a glimpse of a more tailored future, while reminding us of the complexity inherent in treating the human mind.Key Takeaways* Pharmacogenetics studies how genetic variation affects drug response.* Genes influence drug metabolism, receptor sensitivity, and transport mechanisms.* Variations in enzymes (e.g. cytochrome P450) can alter drug levels and effects.* Genetic differences contribute to variability in efficacy and side effects.* Pharmacogenetics supports more personalised approaches to prescribing.* Clinical decisions must still integrate non-genetic factors.* Precision medicine enhances, but does not replace, clinical judgement. This is a public episode. If you'd like to discuss this with other subscribers or get access to bonus episodes, visit drmanaankarray.substack.com/subscribe