However, no significant differences either in basal ganglia nodes of reward circuitry (i.e., caudate, putamen, amygdala, and nucleus accumbens) or in total infratentorial volume, pons, and cerebellum were observed as previously reported (Sullivan et al., 2005, Zahr and Pfefferbaum, 2017). The different methodological and sample characteristics may be contributing to the differences in results. In contrast to more recently abstinent AUD samples used in previous studies, the majority of AUD participants (22/30) in the present study were long-term abstinent and few (8/30) were abstinent for less than six months. Post hoc partial correlations yielded significant positive correlations between abstinence-length and volumes of bilateral caudate, pallidum, cerebral WM, mid posterior corpus callosum, and total subcortical GM, suggesting association of volumes in these regions with abstinence-length, similar to previous findings (Zahr and Pfefferbaum, 2017). However, associations did not survive a CMT. Despite reports of recovery of brain volumes with abstinence, mechanisms of recovery and effects of abstinence-length remain unclear due to factors such as aging (Zahr and Pfefferbaum, 2017). Future studies should investigate recovery of brain volume combining cross-sectional and longitudinal data while controlling for age and abstinence-length, to better understand the extent of recovery in AUD following abstinence.
