The Effectiveness and Cost-effectiveness of Well Parent Japan for Japanese Mothers of Children With ADHD: Protocol for a Randomized Controlled Trial

Background: Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder associated with numerous functional deficits and poor long-term outcomes. Internationally, behavioral interventions are recommended as part of a multimodal treatment approach for children with ADHD. Currently, in Japan, there are limited interventions available to target ADHD. Well Parent Japan (WPJ), a new hybrid parent-training program, provides a culturally acceptable and effective way to help support Japanese children with ADHD and their parents. Objective: This pragmatic multicenter randomized controlled trial aims to provide preliminary evidence about the effectiveness and cost-effectiveness of WPJ evaluated against treatment as usual (TAU) within routine Japanese mental health services. Methods: Mothers of children (aged 6-12 years) diagnosed with ADHD were recruited from child and adolescent mental health care services at three hospital sites across Japan (Fukui, Fukuoka, and Okinawa). The mothers were randomized to receive immediate treatment or TAU. The effectiveness and cost-effectiveness of WPJ over TAU at the end of the intervention and at 3-month follow-up will be evaluated. The primary outcome is maternal parent domain stress in the parenting role. The following secondary outcomes will be explored: child behavior, including severity of ADHD symptoms; parenting practices; emotional well-being; and the parent-child relationship and maternal child domain parenting stress. Data analysis will follow intention-to-treat principles with treatment effects quantified through analysis of covariance using multilevel modeling. An incremental cost-effectiveness ratio will be used to analyze the cost-effectiveness of the WPJ intervention. Results: Study funding was secured through a proof-of-concept grant in July 2018. Approval by the institutional review board for the data collection sites was obtained between 2017 and 2019. Data collection began in August 2019 and was completed in April 2022. Participant recruitment (N=124) was completed in May 2021. Effectiveness and cost-effectiveness analyses are expected to be completed by July 2022 and December 2022, respectively. These timelines are subject to change owing to the COVID-19 pandemic. Conclusions: This is the first multisite pragmatic trial of WPJ based on the recruitment of children referred directly to routine clinical services in Japan. This multisite randomized trial tests the effectiveness of WPJ in children and families by comparing WPJ directly with the usual clinical care offered for children diagnosed with ADHD in Japan. We also seek to assess and compare the cost-effectiveness of WPJ with TAU in Japan.