Cognition and Cortical Thickness in Heavy Cannabis Users

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neuroimaging

Background:

• Heavy cannabis use (HCU) may adversely affect neurocognitive function and brain structure.
• The relationship between cognitive deficits and brain structure in HCU individuals is not well understood.

Purpose of the Study:

• To investigate the associations between cognition and cortical thickness (CT) in males with HCU and male controls.
• To explore potential neuromechanistic underpinnings of cognitive impairments in HCU.

Main Methods:

• Utilized a comprehensive neuropsychological test battery and high-resolution 3T structural MRI.
• Calculated cortical thickness (CT) using the Computational Anatomy Toolbox (CAT12).
• Examined 26 individuals with HCU and 20 healthy controls (HC).

Main Results:

• Individuals with HCU exhibited deficits in verbal learning and verbal working memory compared to controls.
• HCU was associated with reduced CT in medial temporal, orbitofrontal, cingulate, middle temporal, and fusiform cortex regions.
• Verbal learning performance correlated with reduced right entorhinal and left orbitofrontal CT; entorhinal CT linked to cannabis use frequency and amount.

Conclusions:

• Findings support domain-specific cognitive impairments in HCU.
• Abnormal CT in memory-associated brain regions provides a neurobiological explanation for cognitive deficits in HCU.
• The study highlights the impact of HCU on long-term memory processing.