Brain Structural Abnormalities in Addiction Disorders: Transdiagnostic Meta-Analyses

Addictions are commonly classified as either substance-use disorders (SUD) or behavioral addictions (BA). SUDs are well established in taxonomies of mental-health disorders. BAs are only recently recognized as mental-health disorders, with limited and conflicting categorizations. Within each category, individual diagnoses are based on objects of addiction. Despite addiction prevalence, no comprehensive coordinate-based meta-analysis (CBMA) has examined both SUD and BA. The overall goal of this study was to identify GM alterations associated with SUD and BA, both independently and jointly. To this end, a total of 108 peer-reviewed VBM studies reporting case-control contrasts in addiction disorders were identified: 83 reports across five SUD diagnoses (8206 participants); and 25 BA reports across two diagnoses (1572 participants). On these datasets, eight transdiagnostic alteration likelihood estimation (ALE) CBMAs were performed. Three primary ALEs computed cross-study neuroanatomical convergence for: (1) SUD; (2) BA; and (3) Pooled Addictions (SUD + BA). These three primary ALEs were supplemented by five ALE-to-ALE comparison analyses: interaction (SUD + BA to SUD and BA), overlap (SUD on BA), conjunction (SUD on BA), and contrast (SUD > BA; BA > SUD). The independently performed ALEs demonstrated largely distinct anatomical-alteration patterns, overlapping only in the caudate nucleus. The pooled ALE, however, yielded many (n = 24/34) alteration foci not identified in either independent ALE. All newly emerging foci were contributed to by both conditions (SUD and BA) and thus termed "interactive." Functional decoding of all three ALEs consistently identified reward and reward-related cognitive operations as being performed by the brain-regions exhibiting structural alterations in addiction disorders.