Structural MRI findings in long-term cannabis users: what do we know?

Area of Science:

• Neuroimaging
• Neuroscience
• Psychiatry

Background:

• Tetrahydrocannabinol (THC) affects brain morphology in animal models.
• Cannabis is a widely used substance, yet its effects on human brain tissue are under-researched.
• Limited structural neuroimaging studies exist on cannabis use and human brain anatomy.

Purpose of the Study:

• To systematically review structural magnetic resonance imaging studies on cannabis use.
• To examine associations between cannabis use and significant changes in human brain anatomy.
• To identify patterns in brain structure alterations related to cannabis consumption.

Main Methods:

• Systematic review of published structural neuroimaging studies.
• Analysis of studies investigating cannabis users and brain anatomy.
• Inclusion of diverse sample characteristics and methodologies.

Main Results:

• No global structural brain changes were found in cannabis users across studies.
• Six studies reported regional brain alterations, frequently in the hippocampus and parahippocampus.
• Findings suggest inconsistent regional changes, potentially linked to usage patterns and psychopathology.

Conclusions:

• Structural imaging findings suggest THC exposure impacts brain morphology, particularly in medial-temporal regions.
• Inconsistencies across studies indicate a need for further research.
• The prevalence of cannabis use worldwide underscores the importance of understanding its neurological effects.