Background -/- Psychopathy is a mental health disorder characterized by callous and impulsive antisocial behavior, and it is associated with a high incidence of violent crime, substance abuse, and recidivism. Recent studies suggest that the striatum may be a key component of the neurobiological basis for the disorder, although structural findings have been mixed, and functional connectivity of the striatum in psychopathy has yet to be fully examined. Methods -/- We performed a multimodal neuroimaging study of striatum volume and functional (...) connectivity in psychopathy using a large sample of adult male prison inmates (N = 124). We conducted volumetric analyses in striatal subnuclei and subsequently assessed resting-state functional connectivity in areas where volume was related to psychopathy severity. -/- Results -/- Total Psychopathy Checklist Revised and factor 2 scores (which index the impulsive/antisocial traits of psychopathy) were associated with larger striatal subnuclei volumes and increased volume in focal areas throughout the striatum, particularly in the nucleus accumbens and putamen bilaterally. Furthermore, at many of the striatal areas where volume was positively associated with factor 2 scores, psychopathy severity was also associated with abnormal functional connectivity with other brain regions, including dorsolateral prefrontal cortex, ventral midbrain, and other areas of the striatum. The results were not attributable to age, race, IQ, substance use history, or intracranial volume. Conclusions -/- These findings associate the impulsive/antisocial dimension of psychopathy with enlarged striatal subnuclei and aberrant functional connectivity between the striatum and other brain regions. Furthermore, the colocalization of volumetric and functional connectivity findings suggests that these neural abnormalities may be pathophysiologically linked. (shrink)