Cortical morphology of chronic users of codeine-containing cough syrups: association with sulcal depth, gyrification, and cortical thickness.

OBJECTIVES: The study aimed to explore the effects of codeine-containing cough syrup (CCS) exposure on cortical morphology and the relationship between cortical characteristics and CCS dependence. METHODS: Cortical morphometry based on Computational Anatomy Toolbox (CAT12) was used to compare changes in sulcal depth, gyrification, and cortical thickness of the cerebral cortex from 40 CCS users and 40 healthy controls (HCs) with two-sample t tests (p < 0.05, multiple comparison corrected). Relationships between abnormal cortical morphological changes and the duration of CCS use, impulsivity traits, and age of first use were investigated with correlation analysis (p < 0.05, uncorrected). RESULTS: CCS users exhibited significantly increased sulcal depth in the bilateral insula, bilateral lingual, bilateral superior frontal, right precuneus, and right middle frontal regions; increased gyrification in the right precentral cortex; and increased cortical thickness in the bilateral precentral, bilateral precuneus, and right superior temporal cortices compared to HCs. In addition, we found significant correlations between the bilateral insula, right superior frontal cortex, and right precentral gyrus and Barratt Impulsiveness Scale (BIS) total scores. CONCLUSIONS: Chronic CCS abuse may be associated with aberrant sulcal depth, gyrification, and cortical thickness. These morphological changes might serve as an underlying neurobiological mechanism of impulsive behavior in the CCS users. KEY POINTS: • Cortical morphological changes were detected in CCS users. • Increased sulcal depth, gyrification, and cortical thickness of some regions were found in the CCS users. • Positive correlations between cortical morphological changes and BIS total scores were identified.