Smaller regional GM volumes in AUDs relative to HCs were observed in left superior frontal cortex, right insula, left precentral cortex, right putamen, left ABT-263 thalamus, bilateral superior parietal cortex and right supramarginal cortex (Fig. 1, see also Table 2). We did not find regional GM volumes in AUDs that were significantly larger compared to HCs. Finally, no volume differences were found between PRGs and HCs and no volume differences between PRGs and AUDs. GM clusters that were significantly smaller in AUDs compared to HCs were extracted to visualize the proportional average GM volume per group (see Fig. 2). Although we corrected for possible age effects by including age as covariate in our analyses, age could

have influenced our findings of smaller

GM volumes in AUDs. We re-analysed our group differences with a younger subset of AUDs, i.e., AUDs with an age above 47 (n = 15) were excluded from this analysis. This resulted in a group with 54 HCs, 40 PRGs and 21 AUD participants. TIV and smoking status were again included as covariate. Please see Supplementary data Table 1 1 for the demographic information of this group. No group differences were detected with our conservative voxel based whole brain correction threshold of p < 0.05 FDR, probably selleck compound caused by a loss of power due to a smaller number of subjects in the AUD group. However, with a more lenient threshold of FDR p < 0.1 we found very similar results as reported in the total group analyses. AUDs still showed smaller GM volumes in the left superior frontal cortex, postcentral cortex, thalamus and superior parietal cortex (see Table 3). There were still no group differences between HCs and PRGs at this more lenient significance

threshold. We re-analysed our group omitting PRGs who did not meet the diagnostic criteria for pathological gambling based on the CIDI (see supplementary data Table 2 for demographic information). This resulted in a PG group much of n = 35. Smoking status, IQ and TIV were included as covariates in the VBM analyses. Our analyses with this smaller subgroup showed similar results as our main findings. Also, no significant group differences between HCs and PRGs were present at a more lenient threshold of p < 0.1 FDR. The present VBM study investigated whether problem gambling behaviour was associated with reduced GM volumes similar to those that were previously found in AUDs. Although we observed widespread GM reductions in AUDs vs HCs, we did not find any GM abnormalities in PRGs when compared with HCs. As expected we found significantly smaller regional GM volumes in AUDs relative to HCs in the left superior frontal cortex, left precentral cortex, right insula, right putamen, left thalamus, bilateral superior parietal cortex and right supramarginal cortex. These reductions are consistent with previous morphological studies in treatment seeking AUDs (Fein et al., 2009, Jang et al., 2007, Kril and Halliday, 1999, Mechtcheriakov et al.