Impaired mnemonic pattern separation associated with PTSD symptoms paradoxically improves with regular cannabis use
npj Mental Health Research April 24, 2025 Jacob Ross, Bruna Cuccurazzu, Dylan Delmar et al. 1 citation
Posttraumatic stress disorder (PTSD) is linked to poor hippocampal function and disrupted pattern recognition. Cannabis use is common among people with PTSD, but its impact on these cognitive functions is unclear. In 111 participants with varying PTSD symptoms, regular and minimal cannabis users completed a mnemonic similarity task. High PTSD symptoms were associated with reduced pattern separation in minimal users. Regular users with high PTSD symptoms showed greater pattern separation, while those with low PTSD symptoms showed reduced pattern separation. The results suggest regular cannabis use may disrupt pattern separation and hippocampal-dependent processes, but may improve it in individuals with high PTSD symptoms. The cross-sectional design requires longitudinal follow-up to evaluate causal effects.