Association between cortical thickness and alcohol or cannabis use. [A] Brain maps plotting the significance (false discovery rate [FDR]-adjusted −log10(q) values; larger value = greater significance/smaller q-value) of the drink index effect for each area. Greater alcohol use was associated with decreased thickness in a collection of prefrontal cortex (lateral [PFCl], dorsolateral [PFCld]; ventrolateral [PFClv]; medial posterior [PFCmp]), frontal operculum (FrOper), and frontal medial cortex (FrMed) areas. Significant alcohol effects were also found in the parietal medial cortex (ParMed), precuneus (pCun), temporal lobe (Temp), insula (Ins), parietal operculum (ParOper), and intraparietal sulcus (IPS). The color scaling is such that yellow-red signifies those areas showing a significant negative association with drink index scores that survived FDR multiple comparison adjustment, whereas blue denotes areas that were not significant/did not survive FDR adjustment. [B] The same as A, but for the cannabis index. No effects survived FDR adjustment for cannabis use. Note that the coloring of the area labels (e.g., PFCl) corresponds to the network color assignments in Figure 1 (i.e., orange = Control A network). Figure was created using the ggseg (82) R package.