Dose-dependent effect of acute THC on extinction memory recall and fear renewal: a randomized, double-blind, placebo-controlled study.
Psychopharmacology February 1, 2026 Nicole L Zabik, Allesandra Iadipaolo, Craig A Peters et al.
Low doses of delta-9-tetrahydrocannabinol (THC) affect brain regions involved in fear learning and memory in adults with posttraumatic stress disorder (PTSD), with effects persisting up to one week after administration. In a randomized, double-blind, placebo-controlled trial, 36 adults with PTSD received either placebo, 5 mg, or 10 mg of oral THC before fear extinction learning. Twenty-four hours later, the 5 mg group showed greater anterior cingulate cortex and prefrontal cortex activation during early fear renewal. One week later, the 10 mg group showed greater hippocampus activation during extinction recall and prefrontal cortex activation during fear renewal. Dosing and timing are critical for facilitating fear memory processes in PTSD.