Association between intelligence quotient and violence perpetration in the English general population

Data on the relationship between intelligence quotient (IQ) and violence perpetration are scarce and nationally representative data from the UK adult population is lacking. Therefore, our goal was to examine the relationship between IQ and violence perpetration using nationally representative community-based data from the UK.

We analyzed cross-sectional data from the 2007 Adult Psychiatric Morbidity Survey. IQ was estimated using the National Adult Reading Test (NART). Violence perpetration referred to being in a physical fight or having deliberately hit anyone in the past 5 years. We conducted logistic regression analysis to assess the association between IQ (exposure variable) and violence perpetration (outcome variable).

There were 6872 participants aged ⩾16 years included in this study. The prevalence of violence perpetration decreased linearly with increasing IQ [16.3% (IQ 70-79) v. 2.9% (IQ 120-129)]. After adjusting for demographic and behavioral factors, childhood adversity, and psychiatric morbidity, compared with those with IQ 120-129, IQ scores of 110-119, 100-109, 90-99, 80-89, and 70-79 were associated with 1.07 [95% confidence interval (CI) 0.63-1.84], 1.90 (95% CI 1.12-3.22), 1.80 (95% CI 1.05-3.13), 2.36 (95% CI 1.32-4.22), and 2.25 (95% CI 1.26-4.01) times higher odds for violence perpetration, respectively.

Lower IQ was associated with violence perpetration in the UK general population. Further studies are warranted to assess how low IQ can lead to violence perpetration, and whether interventions are possible for this high-risk group.