A structural MRI study found regional differences in both cortical thickness and gray-matter volume among people with methamphetamine use disorder. Those measures should not be treated as interchangeable evidence or a direct explanation of every cognitive deficit.
Zhou and colleagues compared 45 people with methamphetamine use disorder with 43 healthy controls using 3T structural MRI and the MATRICS Consensus Cognitive Battery. The battery covered multiple cognitive domains. Regional volume and cortical thickness were analyzed separately, followed by analyses relating selected structural measures to cognitive performance. No methamphetamine was administered as part of this cross-sectional comparison.
The groups showed reduced gray-matter volume in selected regions, including right insula and left middle frontal areas, and reduced thickness in a partly different set of cortical regions. Some associations depended on the cognitive task and group interaction. Digit-symbol coding, maze performance and sustained attention therefore should not be compressed into one uniform structure–function relationship. The regional mapping was the result, rather than evidence that any single image explains cognition generally.
The design cannot establish whether observed differences developed because of methamphetamine use. Many participants smoked, complicating isolation of drug-specific effects even with statistical adjustment. Abstinence duration was self-reported without the additional biological verification the authors proposed for future work. Regional associations also require replication and cannot be used to infer an individual’s prior level of functioning. An MRI volume or thickness value is not a drug concentration or a legal-capacity measure. The study supports examining more than one anatomical feature while preserving the differences between morphology, measured cognition and causal interpretation.
See structural imaging correlations and nonsignificant group comparisons.