Groups did not differ on any other class of illicit substances except lifetime ecstasy use episodes, therefore we conducted pairwise comparisons controlling for reported ecstasy use. Results were unchanged in 6 of the 8 regions, and differed in 2 regions as follows. In 1 of the 4 superior corona radiata regions, the FA difference between BG+MJ and CON no longer reached significance (p = .08), but BG now had lower FA than BG+MJ in this region (p = .03). In the middle cerebellar peduncle, the FA difference between BG and BG+MJ no longer reached significance (p = .16), but BG+MJ now had lower FA than CON (p = .028) after controlling for ecstasy use.
