Mapping the structural brain network of psychopathy: Convergent evidence from humans and chimpanzees

Psychopathy, a condition marked by profound emotional and interpersonal deficits, has long been hypothesized to arise, in part, from structural abnormalities in the brain. Yet neuroimaging studies have reported widely disparate findings, preventing definitive conclusions. Here, we sought to resolve these discrepancies by testing whether heterogeneous peak locations identified across studies converge on a common brain network. We conducted a systematic literature search of PubMed, Web of Science, EMBASE, and Scopus, identifying 18 studies (20 independent samples) examining whole-brain grey matter volume in psychopathy. Using neuroanatomical data from 1000 healthy participants, we found that grey matter volume at these peak locations varied together, forming a shared network that primarily encompassed paralimbic regions, including the cingulate and insular cortices. We next examined whether psychopathic and personality traits predicted inter-individual variation in grey matter volume within this network in humans (n = 107) and chimpanzees (n = 148). Significant effects were observed in both species, explaining 15-16% and 42-48% of the variance, respectively. Taken together, these findings indicate that psychopathy is best characterized by structural deficits in a distributed neural system rather than isolated regions, providing a unifying account of decades of inconsistent findings and advancing our understanding of its clinical, biological, and evolutionary bases.