Neuroanatomical patterns in adolescents with substance use disorder and their unaffected siblings

Little is known about the underlying neurobiological mechanisms in adolescents with substance use disorder (SUD). We aimed to examine brain morphology in adolescents with SUD and their unaffected biological siblings (SIB), relative to typically-developing controls (TDC) to identify alterations that may be associated with the familial risk for SUD. Structural magnetic resonance imaging analysis included 20 adolescents with SUD, 20 SIB, and 18 TDC. Adolescents with SUD showed lower cortical thickness mainly in the right prefrontal cortex compared to TDC. Importantly, the SIB group also showed lower cortical thickness in the right inferior frontal cortex (IFC) and larger cortical surface area in the isthmus of the cingulate gyrus and precuneus compared to TDC. We did not detect significant differences in subcortical volume or shape between groups. In conclusion, our results suggest that lower cortical thickness in the right IFC might be a candidate endophenotype for SUD. In addition, enlarged cortical surface area in the isthmus of the cingulate gyrus and precuneus might reflect compensatory or protective effects.