By Next Biosciences

22 September 2026

The Trial-and-Error Problem in Psychiatric Care

Mental health conditions span an enormous range, from mild ADHD in a seven-year-old to severe schizophrenia in an adult, and so does the list of medications used to treat them: stimulants, non-stimulants, SSRIs, SNRIs, mood stabilisers, and antipsychotics, each with dozens of individual drugs and dosing options within that.

For most of psychiatric history, choosing the right one has come down to clinical judgement and observation: prescribe, wait several weeks, monitor for effect and side effects, and adjust if needed. This works, but it can mean months of a patient (or a parent) living with a treatment that isn't quite right before landing on one that is.

Genetics is changing that starting point. Pharmacogenomic testing, which analyses how a person's DNA affects the way they process specific medications, is increasingly used alongside clinical judgement to narrow that trial-and-error window considerably.

What the Science Actually Shows

Pharmacogenomics in psychiatry is one of the more evidence-backed areas of precision medicine, not speculative. A few examples:

  • Antidepressants. The Clinical Pharmacogenetics Implementation Consortium (CPIC) has published prescribing guidelines for SSRIs and tricyclic antidepressants based on CYP2D6 and CYP2C19 genotypes, the two enzymes largely responsible for metabolising these medications. A large randomised controlled trial (the PREPARE study) found that genotype-guided prescribing reduced clinically relevant adverse drug reactions by 30%.

  • Antipsychotics. Multiple studies link CYP2D6 metabolism to plasma concentrations of medications like risperidone and aripiprazole, with poor metabolisers at meaningfully higher risk of side effects at standard doses. Regulatory bodies including the FDA and the Dutch Pharmacogenetics Working Group have published dosing guidance reflecting this.

  • ADHD Medication. The evidence base here is younger and less conclusive than for antidepressants and antipsychotics, but a growing number of studies link treatment response to variants in dopamine-related genes, and international psychiatric genetics groups now recognise a role for pharmacogenomics testing with certain ADHD medications, including atomoxetine. 

The common thread: genetics doesn't tell a doctor which condition someone has, or even necessarily which drug will work best. What it can do is flag, before a prescription is written, whether someone is likely to process a given medication unusually slowly or unusually quickly, both of which carry real clinical consequences.

Why This Matters More for Children

For parents of a child newly diagnosed with ADHD, anxiety, or another psychiatric condition, the standard 'try it and see' approach can be a genuinely difficult one to sit through. Watching a child cycle through medications and dosages while a family waits to see what helps, and what doesn't, takes a toll well beyond the clinical picture.

This is precisely where South Africa's treatment landscape makes early, informed decisions especially valuable. National data suggests roughly one in five South African adolescents has a diagnosable mental health condition, yet only around a third receive treatment, and access to specialist child and adolescent psychiatric care remains uneven across provinces. In that context, giving a treating clinician more information before the first prescription, rather than after several unsuccessful ones, is a meaningful way to make each consultation count.

Genetic testing doesn't replace careful clinical assessment, and professional psychiatric bodies internationally are consistent on this point: it isn't a first-line test for everyone, and it can't select the '"correct' medication outright. What it does is add a layer of biological information that clinicians can weigh alongside symptoms, history, and clinical experience, particularly useful when a child has already had a difficult reaction to a first-choice medication, or when a family understandably wants to avoid another round of trial and error.

What This Means for Practitioners

For prescribing clinicians, whether GPs, psychiatrists, or paediatricians managing psychiatric medication, PharmaGene results provide a practical decision-support layer: confirmation of standard dosing, an early flag to consider a dose adjustment, or a signal that a particular drug class may carry a higher risk of poor tolerability for a specific patient.

For psychologists and other allied mental health practitioners who don't prescribe but sit within a patient's broader care team, genetic insights can still be valuable context, informing conversations with a treating psychiatrist or GP, or helping explain to a family why a particular medication trial didn't go as expected. It's worth being clear that PharmaGene informs prescribing decisions rather than replacing the therapeutic and diagnostic work psychologists do; the two roles complement rather than overlap.

How PharmaGene Works

PharmaGene is Next Biosciences' in-house pharmacogenomic test, analysing how genetic variation affects drug metabolism, medication effectiveness, and risk of adverse reactions. The process is straightforward:

  1. The patient completes a test requisition form and provides a simple saliva sample for testing; no blood draw required.

  2. Results are reviewed together with the referring healthcare provider, who translates the genetic findings into practical prescribing decisions.

The test isn't diagnostic, and it isn't only for people already struggling with medication. It's equally useful as a preventative step before starting treatment for the first time, giving both practitioner and patient a clearer starting point.

Learn more about PharmaGene pharmacogenomic testing with Next Biosciences

Frequently Asked Questions

  1. Can genetic testing really help with psychiatric medication? Yes, particularly for antidepressants and antipsychotics, where CYP2D6 and CYP2C19 genotypes are linked to how the body processes these drugs. Evidence for ADHD medication is still developing but growing.

  2. Is PharmaGene suitable for children? Yes. Pharmacogenomic testing is increasingly used in child and adolescent psychiatry, particularly for children who have had a difficult reaction to a first medication or where a family wants more information before starting treatment.

  3. Does PharmaGene diagnose mental health conditions? No. It analyses medication response only and does not diagnose any psychiatric or medical condition.

  4. Can psychologists use PharmaGene results? Psychologists don't prescribe medication, but PharmaGene results can still inform collaborative care, helping a psychologist and prescribing doctor work from the same information.

  5. How is the PharmaGene sample collected? Through a simple saliva sample, with results reviewed alongside the referring healthcare provider.

This article is for educational purposes and is not a substitute for professional medical advice. Any decisions about starting, stopping, or adjusting psychiatric medication should always be made with a qualified healthcare provider.

 

References:

Adolescent mental health in South Africa: what do the numbers say? Africa Check. https://africacheck.org/fact-checks/reports/adolescent-mental-health-south-africa-what-do-numbers-say

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