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Study breakdown

A gene variant and its epigenetic state both influence how THC affects fear processing in the brain

Randomized Controlled TrialPreliminary evidence
The takeaway

Genetic variation at AKT1 rs1130233 and DNA methylation at a nearby site independently influenced how THC altered brain activation during fear processing, with methylation partially mediating the genetic effect.

Genetics researchers, people interested in individual differences in cannabis response, those concerned about cannabis and psychosis risk

Both genetic and epigenetic factors independently predicted THC brain effects

What the researchers found

The number of A alleles at AKT1 rs1130233 and methylation percentage at the CpG11-12 site independently predicted greater THC effects on parahippocampal/amygdala activation during fear processing. The genetic effect was partially mediated by methylation in sections of the left parahippocampal gyrus and hippocampus.

Why it matters

This demonstrates that both inherited genetic variation and modifiable epigenetic factors shape individual responses to THC, helping explain why some people are more vulnerable to cannabis-related anxiety and psychotic symptoms.

The numbers in context

36 healthy males (34 with complete data); 2-session crossover design; THC increased anxiety and psychotomimetic symptoms; AKT1 gene is part of the dopamine signaling cascade

How the study worked

Double-blind, cross-over, randomized placebo-controlled THC administration study in 36 healthy males, with functional MRI during a fear processing task. Genetic (AKT1 rs1130233) and epigenetic (DNA methylation) data were analyzed.

What this study cannot tell us

Small sample of only males, limiting generalizability. Single acute THC dose may not reflect chronic use effects. Epigenetic measurements from blood may not perfectly reflect brain methylation patterns.

How to read the evidence

Small randomized controlled trial with rigorous crossover design but limited to 36 male participants

When this study was published

Published in 2021. Pharmacogenomic research on cannabis response is still in early stages.

The bigger picture

Understanding the genetic and epigenetic factors that modify THC sensitivity could eventually enable personalized risk assessment for cannabis use, identifying individuals who may be particularly vulnerable to adverse psychological effects.

Questions still open

  • Do these genetic and epigenetic factors predict real-world vulnerability to cannabis-related psychosis? Could epigenetic screening be used clinically to assess cannabis risk? Do females show the same patterns?

Common questions

Do genes affect how THC impacts the brain?
Yes. This study found that a specific variant in the AKT1 gene, part of the dopamine signaling pathway, predicted greater THC effects on brain regions involved in fear processing.
What role does epigenetics play in THC response?
DNA methylation near the AKT1 gene independently influenced THC brain effects and partially mediated the genetic effect. This suggests both inherited and modifiable factors shape individual vulnerability to THC.

Read the original research

Epigenetic Mediation of AKT1 rs1130233's Effect on Delta-9-Tetrahydrocannabinol-Induced Medial Temporal Function during Fear Processing.

Brain sciences, 11(9)

Citation

Blest-Hopley, Grace; Colizzi, Marco; Prata, Diana; Giampietro, Vincent; Brammer, Michael; McGuire, Philip; Bhattacharyya, Sagnik. (2021). Epigenetic Mediation of AKT1 rs1130233's Effect on Delta-9-Tetrahydrocannabinol-Induced Medial Temporal Function during Fear Processing.. Brain sciences, 11(9). https://doi.org/10.3390/brainsci11091240

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