A prospective cohort study followed 109 nearly MDMA-naive subjects for 12 months to determine whether cognitive deficits appear after beginning MDMA use. Twenty-three subjects who used more than 10 MDMA pills (mean 33.6 pills) were compared with 43 subjects who used no illicit drugs besides cannabis. Groups did not differ in age, intelligence, cannabis, alcohol, or other lifestyle confounders. MDMA users showed significant impairments in immediate and delayed recall of a visual paired associates learning task compared with controls, but no differences emerged on other tests of memory, learning, or executive function. The findings suggest MDMA specifically impairs visual paired associates learning, possibly due to serotonergic dysfunction in the hippocampus.
Cannabis-dependent men show exaggerated cognitive performance deterioration during psychosocial stress compared to controls, despite reporting similar stress levels and cardiovascular responses. Brain imaging revealed that this performance decline was accompanied by reduced activity in the precuneus and increased connectivity between the precuneus and the superior frontal gyrus during stress exposure. The findings provide first evidence linking chronic cannabis use to altered neural stress processing, specifically deficient recruitment of the precuneus, which may underlie stress-induced cognitive impairments in cannabis users.
The medial prefrontal cortex (mPFC) is central to emotional experience, with a functional gradient along its dorsal-ventral axis: dorsal regions primarily engage in negative emotions, while ventral subdivisions facilitate positive (safety) experiences and show a duality—representing emotions abstractly while generating individualized interpretations. During emotion regulation, the dorsal mPFC supports explicit-control strategies like reappraisal, and the ventral mPFC mediates implicit-automatic regulation through extinction learning. Through interactions with the default mode network and other brain networks, the mPFC enables the construction of nuanced, contextualized emotional experiences fundamental to adaptive behavior. Understanding these mechanisms may advance affective neuroscience and inform therapeutic approaches for mental disorders with default mode network dysfunction.
Cannabis-dependent men show blunted neural and behavioral responses to social reward, specifically when receiving touch from a woman compared to a man. In a study of 23 abstinent cannabis-dependent men and 24 matched non-using controls, dependent users reported less pleasure and showed reduced striatal brain activation during female (versus male) touch, with stronger alterations linked to greater lifetime cannabis exposure. Neural processing of pleasant touch itself remained intact. The findings suggest that cannabis dependence produces lasting neuroadaptations in reward processing similar to other drugs of abuse, but deficits depend on social context.