Reliability of the "Parma Scale" for forensic psychiatric treatment evaluation: preliminary findings in a sample of prisoners with mental disorder

Objectives Routine monitoring of treatment outcomes has been poorly implemented in Italian forensic psychiatric practice. This is also for lacking of reliable tools. Thus, the "Parma Scale" (Pr-Scale) was developed. The specific aim of this study was to examine the reliability of the Pr-Scale as preliminary investigation on its psychometric properties. Methods Test-retest and interrater reliability was assessed in a sample of prisoners with mental disorder using Intra-Class Correlation (ICC) and stability coefficients. Internal consistency for the Pr-Scale total score was also calculated using the Cronbach alpha statistic. Results Thirty male adult inmates with mental illness were recruited within the Parma Penitentiary Institute (PPI). Our results showed good to excellent interrater and test-retest reliability for the Pr-Scale scores, as well as an acceptable internal consistency for the Pr-Scale total score. Conclusions The findings of this study seem to support the administration of the Pr-Scale in forensic psychiatric settings as reliable tool for routine monitoring of treatment outcomes. However, future studies to carefully investigate other crucial psychometric properties of the Pr-Scale (e.g. concurrent validity, sensitivity to measure scores' longitudinal changes, predictive validity for recidivism risk) are needed.