Under the acute influence of THC, healthy volunteers showed a heightened tendency to form false memories compared to those given a placebo. In a double-blind, randomized trial, 64 participants completed memory tasks—including associative word lists and two virtual-reality misinformation scenarios—immediately while intoxicated and again one week later while sober. Intoxicated individuals exhibited a stronger false-recognition bias, especially when test items were weakly associated with studied material, and were more susceptible to misinformation in eyewitness and perpetrator scenarios. These false-memory effects were largely confined to the acute intoxication phase. The findings suggest that cannabis increases false-memory proneness and have practical implications for police interviews with suspects and eyewitnesses.
Cannabis intoxication and a history of regular cannabis use are linked to a more liberal response criterion in memory tasks, leading to higher false recognition of unrelated items. In a field study using the Deese/Roediger-McDermott (DRM) paradigm, regular cannabis consumers who were acutely intoxicated (n = 53), regular cannabis consumers who were sober (n = 50), and cannabis-naïve controls (n = 53) completed a memory test. False memory rates for critical lures did not statistically differ between groups, but both intoxicated and sober cannabis consumers falsely recognized more unrelated items than controls. Cannabis-naïve individuals showed higher memory accuracy compared with the intoxicated group.