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A recent study published in *JAMA Network Open* investigated how chronic cannabis use—both recent and lifetime—affects brain function. Researchers analyzed data from 1,003 adults aged 22–36 using functional MRI scans during various cognitive tasks.
The study found that heavy cannabis users, defined as those with 1,000+ uses or recent THC-positive urine tests, showed reduced brain activation in key areas like the dorsolateral prefrontal cortex and anterior insula—regions vital for decision-making and memory.
While recent cannabis use linked to lower brain activation was observed, these effects were not statistically significant after accounting for other factors like education and race. However, behavioral performance on tasks requiring working memory declined among recent users, suggesting acute exposure may temporarily impair cognitive efficiency.
Lifetime heavy users also exhibited reduced activation in critical brain areas, even when excluding those with recent use. This underscores the potential for long-term neural adaptations due to chronic cannabis exposure, such as decreased cannabinoid receptor density in regions like the dlPFC and anterior insula.
Sex-specific differences were noted, with male participants showing reduced brain activation during motor tasks but not female counterparts. The study also found correlations between brain activation and measures of education, intelligence, and verbal episodic memory, though no significant links were observed between cannabis dependence diagnoses and brain outcomes.
Overall, the findings demonstrate that heavy cannabis use—whether recent or lifetime—can impair brain function in areas essential for memory and cognitive control. While the study highlights associations, it does not establish causation, emphasizing the need for further research to better understand long-term impacts.
These results stress the importance of educating individuals about the risks of cannabis use, particularly for activities requiring focus and decision-making, such as driving or workplace settings. Public health policies must consider the cognitive risks associated with heavy cannabis use, and future longitudinal studies are crucial to determine causality and long-term effects.
Source: https://www.news-medical.net/news/20250128/Study-shows-long-term-cannabis-use-disrupts-critical-brain-processes.aspx