A simple, low-cost approach outperforms genetic testing
STUDY: Nierenberg AA et al, Journal of Clinical Psychopharmacology 2026
STUDY TYPE: Randomized, unblinded, comparative-effectiveness trial
FUNDING: Patient-Centered Outcomes Research Institute; no pharmaceutical industry funding
Background
Two simple steps make a big difference for patient’s outcomes:
- Rating their symptoms at every visit (and graphing it)
- Following treatment guidelines closely
In one randomized trial, that process raised remission rates from depression 2.5-fold. Genetic testing, in contrast, has yet to make that kind of difference. This study tested gene-guided treatment against the lost-cost technique of following guidelines.
The Study
- 201 adults with major depression at 5 academic medical centers.
- Randomized to pharmacogenomic testing plus guideline-informed care, or guideline-informed care alone (CANMAT guidelines).
- Followed 12 months; primary outcome was well-being, with depression severity and function as secondary measures.
Results
Well-being improved substantially in both groups over the year, but pharmacogenomic guidance made no difference (model-based difference -0.6, 95% CI -1.8 to 0.5, p=.270). None of the four secondary outcomes differed: depression severity, physical function, social participation, and clinical adjustments (all p > 0.35). Analyzing the data by severity, prior treatment failures, or comorbidity also showed no benefit.
Clinicians who used genetic testing often avoided medications with moderate gene-drug interactions, and this practice lead to no gains in well-being.
Limitations
Samples were limited to academic centers. COVID-19 cut the target sample roughly in half. Neither patients nor clinicians were blinded (although that usually favors genetic testing).
Practice Implications
Here’s a few reasons why genetic testing may fail:
- Antidepressants have wide therapeutic windows and are metabolized through multiple pathways, so pharmacokinetic genes don’t tell us much.
- That is why we don’t check serum levels for most antidepressants, and why there are few actionable drug-gene interactions.
- Around 30-40% of a metabolic enzyme’s activity is determined by environment, not genes.
With those limitations, most genetic results are misleading rather than actionable. Guidelines, in contrast, are a richer source of information, distilling decades of clinical trials into actionable steps.
—Chris Aiken, MD
Director, Psych Partners
Editor in Chief, Carlat Psychiatry Report
