Medical XpressLargest Study Ever Done on Cannabis and Brain Function Finds Impact on Working Memory

A groundbreaking study published in JAMA Network Open has demonstrated significant correlations between cannabis use and working memory function. The research, involving more than 1,000 young adults aged 22-36, utilized brain imaging technology to assess cognitive performance across seven distinct tasks. The findings reveal substantial impacts on brain activity during working memory tasks, particularly among heavy users.

Key Points:

• The study identified reduced brain activity in 63% of heavy lifetime cannabis users (>1,000 times) during working memory tasks, with 68% of recent users showing similar effects. These changes manifested in specific brain regions: the dorsolateral prefrontal cortex, dorsomedial prefrontal cortex, and anterior insula.
• Researchers employed rigorous statistical standards, including false discovery rate correction, across seven cognitive domains: working memory, reward, emotion, language, motor skills, relational assessment, and theory of mind. Working memory emerged as the only domain showing statistically significant impairment.
• Clinical categorization defined heavy users as those with >1,000 lifetime uses, moderate users as 10-999 lifetime uses, and nonusers as <10 lifetime uses. This classification system provides clear parameters for clinical assessment.
• The study suggests potential benefits from abstaining before cognitive tasks, though researchers note that abrupt cessation among heavy users may disrupt cognition, indicating the need for careful management of cannabis use patterns.
• The research identifies specific brain regions involved in cognitive functions like decision-making, memory, attention, and emotional processing as being particularly affected by cannabis use.

“People need to be aware of their relationship with cannabis since abstaining cold turkey could disrupt their cognition as well. For example, heavy users may need to be more cautious.”
— Joshua Gowin, PhD; Assistant Professor of Radiology at the University of Colorado School of Medicine on the University of Colorado Anschutz Medical Campus

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