Cannabis use was associated with reduced working memory function, according to a new study published in JAMA Network Open. The research analyzed over 1,000 cannabis users aged 22-36 who underwent functional MRI brain scans while performing cognitive tests.

Key findings:

• Heavy lifetime cannabis use (>1,000 times) linked to decreased activity in brain areas controlling working memory
• Effects were present even after excluding recent cannabis use
• Working memory impacts daily tasks like driving, following instructions, and maintaining conversations
• Changes were most concerning in young adults with developing brains

Study details:

• Participants: ~50% female, 75% white
• Usage categories:
  • Heavy: >1,000 lifetime uses
  • Moderate: 10-999 lifetime uses
  • Non-users: <10 lifetime uses
• Seven cognitive tests measured working memory, reward processing, emotions, language, and motor skills
• THC detected through urine samples

Important considerations:

• Study cannot prove direct causation between cannabis and brain damage
• Effects may last 2-4 weeks after use
• Even "social users" may experience cognitive effects
• Impact varies by age and individual circumstances

Medical implications:

• Cannabis can still have legitimate medical benefits
• Patients should discuss risks and benefits with healthcare providers
• Effects may differ between recreational and medical users
• Other medications can similarly impact memory and cognition

Best practices:

• Abstain before cognitively demanding tasks
• Consider age when evaluating cannabis use
• Be aware of potential impacts on daily functioning
• Discuss usage with healthcare providers for informed decisions

The study adds to growing evidence that frequent cannabis use may impact cognitive abilities, particularly working memory, though more research is needed to understand long-term effects across different populations and usage patterns.

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