Abnormal Cortical Thickness Development in Young Adults With Heavy Cannabis Use: A Longitudinal Study

Area of Science:

• Neuroscience
• Addiction Research
• Neuroimaging

Background:

• Cannabis is a widely used illicit substance with potential long-term cognitive and structural brain effects.
• Limited research exists on dynamic cortical thickness (CT) changes related to cannabis use, particularly in heavy cannabis users (HCU).

Purpose of the Study:

• To investigate longitudinal changes in cortical thickness (CT) in young adults with heavy cannabis use (HCU) over a 3-year period.
• To examine the relationship between the severity of cannabis use and CT alterations in HCU.

Main Methods:

• Longitudinal study design tracking young adults with HCU from baseline to 3-year follow-up.
• Analysis of cortical thickness (CT) changes across various brain regions using neuroimaging techniques.
• Correlation analysis between the Cannabis Use Disorders Identification Test (CUDIT) scores and CT in the left lateral orbitofrontal cortex (OFC).

Main Results:

• Significant group and time effects on CT were observed in several brain regions, including the left lateral frontal cortex, medial frontal cortex, posterior cingulate cortex, and insula.
• Young adults with HCU showed a significant decrease in left lateral OFC CT at follow-up compared to baseline and a control group.
• A positive correlation was found between CUDIT scores and left lateral OFC CT, indicating greater use severity was associated with reduced thickness.

Conclusions:

• Prolonged cannabis use is associated with structural brain changes, specifically a reduction in left lateral orbitofrontal cortex (OFC) thickness.
• These CT changes in the left lateral OFC may contribute to impaired decision-making, impulse control, and emotional processing, potentially worsening addictive behaviors.
• The findings offer crucial insights into the neural mechanisms underlying cannabis addiction and its structural brain correlates.