Developing and testing of an assessment tool for appropriate psychotropic drug prescribing in people with intellectual disabilities.

Background: Prescribing psychotropic drugs often leads to long-term use in people with intellectual disabilities. In this population, polypharmacy is also common, likely because of the high frequencies of comorbid somatic, behavioural and mental disorders, while the vulnerability for medication side effects is high. Therefore, there is a risk of inappropriate prescribing of psychotropic drugs in people with intellectual disabilities.

Objectives: This study aimed to develop a tool to assess the appropriateness of psychotropic drug prescriptions in people with intellectual disabilities and to test its psychometric properties.

Design: In this study, we used a mixed-methods design. In a qualitative phase, we developed the tool, followed by a quantitative phase, to evaluate its psychometric properties.

Methods: We used a modified Delphi procedure consisting of a preparation phase and three Delphi iterations to develop the tool and to determine which items encompass the concept of appropriate psychotropic drug prescribing. A weighting round was conducted to determine a summated index score. Finally, the test-retest reliability, the interrater reliability and the convergent validity of the tool were investigated.

Results: The Delphi panel, with 37 field expert participants, agreed on the content of the tool, including seven domains (indication, dosage, duration, duplication, interactions, evaluation of effect and evaluation of side effects) that should be assessed regarding appropriate psychotropic drug prescribing. The test-retest reliability and the interrater reliability turned out to be moderate to perfect for five of the seven domains, except the domains 'evaluation of effect' and 'evaluation of side effects', although no interrater agreement was found in the domain 'duration'. The convergent validity was slight.

Conclusion: In conclusion, this study resulted in the development of a reliable tool to support prescribers in clinical practice in the appropriate prescribing of psychotropic drugs in people with intellectual disabilities.