Examining the cognitive contributors to violence risk in forensic samples: A systematic review and meta-analysis

A systematic review and meta-analysis was undertaken to quantitatively summarise the association between measures of cognitive abilities (e.g., neuropsychological and clinical measures, and risk assessments with a cognitive component) and violent outcomes. After acknowledging that existing reviews in this area have largely focused on executive functions and specific diagnostic groups only, the review adopted a broader approach, first examining factors which differentiate violent from non-violent offenders (part one), followed by separately analysing the neuropsychological correlates of violence (part two). Forty-two studies were included in the analyses, and 12 individual neuropsychological domains were examined in part one, and five in part two. The findings from this study revealed a large range of effect sizes with wide confidence intervals, highlighting significant heterogeneity due to methodological differences between studies, calling for a consensus to be reached on the neuropsychological risk factors which are most relevant to violence risk, to bring more focus and specificity to the literature. Measures of impulsivity, inattention, and lack of insight boasted significant correlations with prospectively measured violent outcomes, revealing their potential to add a small amount of incremental validity to existing risk assessments.