Impulsiveness as a factor in sexual offending by people with mild intellectual disability

Background  It has been suggested that sexual offending by people with intellectual disability (ID) results from a pattern of impulsive behaviour that is consistent with psychosocial disadvantage, rather than sexual deviancy. This study aimed to explore this hypothesis by assessing levels of impulsiveness in sexual offenders, non-sexual offenders and nonoffenders with mild ID. Method  Impulsiveness was assessed using a modified version of the Barratt Impulsiveness Scale (11th edition). Total impulsivity scores were compared between sexual offenders, non-sexual offenders and non-offenders, all with mild ID. Results  There was a significant difference in the levels of impulsiveness between sexual offenders and non-sexual offenders with ID (t = 2.83, P < 0.01). The sexual offenders were less impulsive than non-sexual offenders. Conclusions  This study did not support the hypothesis that sexual offending by people with ID is better explained by impulsive behaviour rather than sexual deviancy. It supports recent findings that among the general population, sexual offenders are less impulsive than controls and violent offenders.