Polygenic risk score
Post-Traumatic Stress Disorder (PTSD)
ICD-11 6B40 · Stress-related disorders
The PTSD polygenic risk score summarizes common-variant liability for Post-Traumatic Stress Disorder, using the 2024 Nievergelt PGC meta-analysis — over 1.2 million participants. PTSD is unique in psychiatric genetics: trauma exposure is a necessary precondition, so the PRS captures post-trauma vulnerability rather than baseline risk.
PTSD polygenic risk describes vulnerability to developing PTSD after trauma exposure — not a prediction of trauma or of PTSD in its absence.
At a glance
PTSD is the only psychiatric condition that requires an environmental trigger by definition. Your score reflects common-variant susceptibility to developing PTSD *given* trauma exposure, not the likelihood of trauma itself.
Post-Traumatic Stress Disorder develops after exposure to a traumatic event in a subset of trauma-exposed individuals. Twin heritability for PTSD given trauma exposure is around 30-40%. The 2024 PGC-PTSD GWAS is the largest published to date and identifies common variants influencing vulnerability to develop PTSD after trauma exposure.
What the GWAS actually found
The 2024 PGC PTSD meta-analysis (Nievergelt et al., Nature Genetics) combined 1,222,882 European-ancestry participants (137,136 cases) and an additional admixed-American cohort for a total N of 1,280,933. It identified 95 genome-wide significant loci — a large jump from prior PTSD GWAS. Top-hit genes named in the paper include GRIA1 (glutamate receptor), FOXP2 (a regulator of neurodevelopment), and PCLO (presynaptic scaffolding).
PTSD heritability estimates vary by cohort and sex — twin studies report roughly 0.30–0.40, lower in men than women. The architecture overlaps substantially with MDD (rg ≈ 0.62) and with anxiety spectrum, reflecting shared stress-response biology.
Full citation: Latest PGC PTSD GWAS (2024). Nature Genetics. PMID: 38637617..
How to read your percentile
Below 25th
Lower common-variant liability than most of the reference cohort. Trauma exposure remains the dominant risk factor; genetics describe conditional vulnerability, not immunity.
25th–75th
Typical range — near the population average. Clinical PTSD outcome depends on trauma severity, social support, and access to early intervention.
Above 75th
Elevated common-variant liability. If you have trauma exposure, early evidence-based intervention (trauma-focused CBT, EMDR) substantially reduces PTSD onset. The PRS is not clinically actionable on its own.
What this does not tell you
PTSD requires trauma exposure — a PRS alone cannot predict PTSD in someone who has not experienced qualifying trauma. The score instead describes conditional probability: given trauma exposure, the relative likelihood of developing PTSD rather than resilient recovery.
The PRS does not predict trauma type, symptom trajectory, or treatment response. Early psychological intervention (trauma-focused CBT, EMDR) has strong interventional evidence for reducing PTSD onset — these are clinical interventions, not genetically predicted outcomes.
Related traits
Post-Traumatic Stress Disorder (PTSD) shares common-variant architecture with several other psychiatric conditions. Genetic correlations (rg) reflect how often the same variants move risk for both traits in the same direction.
Frequently asked questions
Does a high PTSD PRS mean I will develop PTSD?
Not without trauma exposure. PTSD by definition requires a qualifying traumatic event. The PRS describes conditional vulnerability: given trauma exposure, a higher PRS corresponds to a modestly higher probability of developing PTSD rather than resilient recovery.
How accurate is the PTSD PRS?
The 2024 Nievergelt meta-analysis PRS explains roughly 2% of variance in liability in European-ancestry validation samples. Accuracy is lower in non-European ancestries and varies by sex.
Can this score predict which traumas will cause PTSD?
No. Trauma type, severity, and recency are strong independent risk factors for PTSD that the PRS does not capture. Interpersonal trauma, childhood trauma, and repeated exposure carry higher PTSD rates than single-event non-interpersonal trauma regardless of PRS.
What's the difference between PTSD and complex PTSD (cPTSD)?
Complex PTSD (ICD-11 6B41) is distinguished by sustained-trauma history and additional symptoms including affect dysregulation, negative self-concept, and interpersonal disturbance. Current PTSD GWAS do not cleanly separate PTSD from cPTSD — subtype-specific scoring is an open research area.
Sources
- Nievergelt et al. 2024, Nature Genetics. doi.org/10.1038/s41588-024-01707-9
- PGC PTSD Working Group. pgc.unc.edu/for-researchers/working-groups/ptsd-workgroup/
- Nievergelt et al. 2019 — PTSD GWAS precursor. doi.org/10.1038/s41467-019-12576-w
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