Development of the psychopathology instrument for Mentally Retarded Adults-Sexuality Scale (PIMRA-S).

Matson et al. (1994) built a new rating scale for adults with mild or moderate intellectual disability. The scale is called the PIMRA-S. It looks for sexual behavior problems.

Staff who know the adult fill out the form. The study ran early checks on reliability and validity.

The first numbers looked good. The scale held together and gave steady scores.

It also caught real differences. Adults who lived in large institutions or who had a history of abuse showed more sexually aberrant behavior than those who did not.

Nine years later Katz et al. (2003) went a step further. They made the QACSO, a self-report scale that asks men with ID about their own antisocial sexual thoughts. The QACSO does not replace the PIMRA-S, but it lets you hear directly from the client instead of only from staff.

Petry et al. (2009) and Barisnikov et al. (2019) followed the same playbook. Each team built a new questionnaire for adults with ID, ran small psychometric checks, and reported solid internal consistency. Together these papers show a clear path: start with a tight scale, test it with a small group, then refine.

Farrant et al. (1998) and Laugeson et al. (2014) remind us why we need good tools in the first place. They taught sexual abuse prevention or relapse-prevention skills to adults with ID. Gains made in the training room often vanished in real-world settings. A reliable scale like the PIMRA-S can flag who needs heavier generalization support before training even starts.

If you work with adults who have ID, you now have a quick staff rating scale that spots possible sexual behavior problems. Use it during intake, re-evaluation, or when behavior suddenly changes. Pair it with the newer QACSO if you want the client’s own voice. Early flags mean earlier safety plans, better treatment matches, and clearer data for the team.