Sexual offending in adults with intellectual disabilities: A systematic review evaluating risk assessment measures for sexual offending in adults with intellectual disabilities; &, An interpretative phenomenological analysis on the experiences of families of adults with an intellectual disability charged with sexual offence

Abstract

This thesis portfolio is submitted in fulfilment of the requirements for the Doctorate in Clinical Psychology. The portfolio comprises two studies that explore aspects of sexual offending in adults with intellectual disabilities (ID). The first study is a systematic review evaluating the predictive validity of risk assessment measures for sexual offending in adults with ID. A systematic search across five electronic databases identified nine eligible studies, which were critically appraised and synthesised following PRISMA guidelines. Findings revealed considerable variability in predictive performance across tools. Structured Professional Judgement (SPJ) tools, particularly those specifically developed for ID populations, demonstrated superior predictive validity for sexual recidivism compared to general actuarial measures. However, methodological limitations across studies, including inconsistent definitions of recidivism and ID, should be noted. The implications for clinical practice and future research are discussed, with particular emphasis on the need for validated, ID-specific risk assessment measures. The second study is an empirical investigation using Interpretative Phenomenological Analysis (IPA) to explore the lived experiences of family members of adults with ID who have been charged with a sexual offence. Semi-structured interviews were conducted with five participants (three mothers and two brothers) to explore the experiences and impacts of the offence. The analysis identified four Group Experiential Themes: ‘Sense-making’, ‘Weight of Carer's Identity’, ‘Living in Fear’, and ‘Navigating the System’. Participants described complex processes of reconciling prior perceptions of their relative, heightened caregiving burdens, experiences of stigma and hypervigilance, and significant challenges accessing adequate systemic support. The findings contribute to an under-researched population and underscore the need for trauma-informed, family-inclusive services. Together, the two studies provide a novel contribution to understanding both risk prediction in ID sexual offending populations and the broader systemic effects on families. Recommendations for clinical practice and future research are outlined