Supplementary Materials s24

SUPPLEMENTARY MATERIALS

Validation analysis: correlation analysis between the cortical thickness and clinical characteristics and impulsive behavior in a voxel based manner

We repeated the correlation analysis between cortical thickness and duration of DXM use, initial age of DXM use as well as impulsive behavior within the DXM-dependent adolescents and young adults by using a voxel based manner. Notably, we also found a significant negative correlation between the thickness in the DLPFC.L and the initial age of DXM use (Supplementary Fig. 1), and a significant positive correlation between the thickness in the DLPFC.L and the BIS total scores (Supplementary Fig. 2) in the DXM-dependent adolescents and young adults.

Supplementary Figure 1. The initial age of DXM use negatively correlated with the cortical thickness of left DLPFC, left PreC, left FUS, bilateral SFG, and right IPL, right LING and right MFG in DXM-dependent adolescents and young adults. Color bars indicate the T value. (p < 0.05, Alphasim corrected). DLPFC, dorsal lateral prefrontal cortex; PreC, precuneus; FUS, fusiform; SFG, superior frontal gyrus; IPL, inferior parietal lobel; LING, lingual gyrus; MFG, middle frontal gyrus. Supplementary Figure 2. BIS total scores positively correlated with the cortical thickness of left DLPFC, left PreCG, left PCC, and left MTG and left SMG in DXM-dependent adolescents and young adults. Color bars indicate the T value. (p < 0.05, Alphasim corrected). DLPFC, dorsal lateral prefrontal cortex; PreCG, precentral gyrus; PCC, posterior cingulate cortex; MTG, middle temporal gyrus; SMG, supramarginal gyrus.

Supplementary Table. Details for the DXM-containing cough syrups dependent adolescents and young adults Participants Age Age of initial DXM Duration Mean dose of DXM use (years) use (years) (years) per day (ml/d) Subject01 23.00 18.00 5.00 300.00 Subject02 24.00 21.00 3.00 1200.00 Subject03 29.00 24.00 5.00 60.00 Subject04 28.00 20.00 8.00 720.00 Subject05 19.00 16.00 3.00 360.00 Subject06 20.00 13.50 6.50 480.00 Subject07 20.00 19.00 1.00 600.00 Subject08 30.00 25.50 4.50 360.00 Subject09 29.00 24.00 5.00 720.00 Subject10 26.00 18.00 8.00 360.00 Subject11 21.00 18.00 3.00 1000.00 Subject12 22.00 20.00 2.00 480.00 Subject13 24.00 18.00 6.00 240.00 Subject14 25.00 20.00 5.00 120.00 Subject15 22.00 16.00 6.00 360.00 Subject16 28.00 23.00 5.00 120.00 Subject17 24.00 21.00 3.00 1800.00 Subject18 25.00 20.00 5.00 300.00 Subject19 24.00 18.00 6.00 120.00 Subject20 22.00 16.00 6.00 240.00 Subject21 20.00 14.00 6.00 360.00 Subject22 29.00 21.00 8.00 480.00 Subject23 22.00 16.00 6.00 240.00 Subject24 22.00 18.00 4.00 600.00 Subject25 22.00 15.00 7.00 360.00 Subject26 23.00 17.00 6.00 300.00 Subject27 21.00 16.00 5.00 1200.00 Subject28 23.00 21.50 1.50 60.00 Subject29 24.00 19.00 5.00 720.00 Subject30 25.00 22.00 3.00 60.00 Subject31 24.00 18.00 6.00 720.00 Subject32 23.00 17.00 6.00 360.00 Subject33 28.00 20.00 8.00 360.00 Subject34 23.00 19.00 4.00 600.00 Subject35 27.00 19.00 8.00 360.00 Subject36 28.00 20.00 8.00 300.00 Subject37 18.00 14.00 4.00 1200.00 Subject38 26.00 22.00 4.00 60.00