“Disentangling the putative impact of cannabis on brain morphology from other comorbid substance use is critical. After controlling for the effects of nicotine, alcohol and multi-substance use, this study aimed to determine whether frequent cannabis use is associated with significantly smaller subcortical grey matter volumes.
After correcting for multiple testing (p=0.007), cannabis use was unrelated to any subcortical ROI. However, maximum nicotine use was associated with significantly smaller thalamus volumes in middle-age males.
In exploratory analyses based on young adult and middle age samples, normal variation in cannabis use is statistically unrelated to individual differences in brain morphology as measured by subcortical volume.”