Psychometric properties of a new decision-making Capacity Assessment Tool for people with substance use disorder: the CAT-CAT

Individuals with substance use disorder (SUD) often present with cognitive impairments, which may impede their ability to make decisions for themselves, including treatment-related decisions. It is therefore important to assess whether individuals with SUD have adequate decision-making capacity. Indeed, there have not been any capacity assessment tools tailored for use with SUD populations that demonstrate adequate psychometric properties or that have the strong ethical foundation that is required of capacity assessment tools. The Compulsory Assessment and Treatment-Capacity Assessment Tool (CAT-CAT) was designed to fill this gap in the literature. Therefore, the aim of this study was to establish the interrater and test-retest reliability, and discriminative validity of the CAT-CAT. The first of this two-part study recruited healthcare professionals in New Zealand and asked them to conduct a capacity assessment on two hypothetical clients. Generally, excellent interrater reliability (ρ =. 998 overall) and test-retest reliability (ρ =. 996 overall) was found. The CAT-CAT has exhibited reliability that was at least comparable to widely used capacity assessment tools for other pathologies. The second part of this study involved cognitively normal individuals undergoing capacity assessments to investigate the hypothesis that individuals that do not lack capacity will obtain scores significantly higher than 50% in each section of the CAT-CAT. This hypothesis was met with highly significant results. To conclude, preliminary data suggest that the CAT-CAT has excellent reliability and correctly classifies those with capacity.