Development of a Pediatric Version of the Study Medication Withdrawal Questionnaire (SMWQ)

OBJECTIVES: Many commonly used ADHD medications cause withdrawal symptoms in adults and children. The SMWQ is among a group of measures suggested to assess withdrawal symptoms in clinical trials. However, the SMWQ has so far not been adapted for use in children and adolescent populations.

METHODS: We conducted a literature review to identify ADHD medication withdrawal symptoms and other existing medication withdrawal assessment tools. Guided by expert clinician input and literature review findings, we drafted multiple age-appropriate withdrawal questionnaires for evaluation in qualitative interviews with ADHD children, adolescents, and parents. The instruments were revised for another round of interviews resulting in pediatric self-report and observer-reported versions. Exploratory analyses of initial data from adolescent trial participants were used to evaluate the performance of the self-report version and to confirm a single-factor structure.

RESULTS: 15 children and adolescents aged 8-17 years and 11 parents of children aged 4-7 years took part in concept elicitation and cognitive debriefing interviews using the draft pediatric withdrawal questionnaires. After iterative rounds of edits and review, self-report and pediatric observer versions of an 11-item measure were finalized for use in a clinical trial. Data from 108 trial participants provided support for an 11-item self-report version of the measure completed by children and adolescents with ADHD aged 8-17 years with internally reliability (Cronbach’s alpha 0.74) and clear regression results of binary item endorsement predicting the total frequency score (adj r² 0.87).

CONCLUSIONS: The adapted SMWQ for pediatric and adolescent populations with ADHD is a new measure with appropriate content validity for assessing study medication withdrawal in pediatric ADHD trials. Initial evaluation of the self-report version shows appropriate measurement properties. Evaluation of the measurement properties for the parent-report version is pending and subject to data availability from the ongoing trial.