Socioeconomic burden of adult attention deficit/hyperactivity disorder in Japan: a nationwide cross-sectional observational study

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that negatively affects social, academic, and occupational functioning. Although more common in children, ~ 2. 5% of adults worldwide have ADHD. In this cross-sectional observational study, we estimated the annual socioeconomic burden of adults with ADHD in Japan (societal perspective). We used retrospective data from the JMDC claims database, a prospective web-based survey of adults with self-reported ADHD, adult family members living with an adult with ADHD, and adults without ADHD who had an Adult ADHD Self-Report Scale score < 4 (control population), and Japanese government agency websites to estimate medical costs (outpatient costs and drug costs), social welfare costs (disability pensions and employment support services), and productivity losses due to unemployment, low income, absenteeism, and presenteeism. In addition to the base-case analysis, we conducted scenario and sensitivity analyses to examine the effects of changing estimation and matching methods on costs, as well as a subgroup analysis of costs stratified by the number of psychiatric comorbidities. Cost estimates were based on 30, 730 adults with an ADHD diagnosis in the JMDC database and, from the web-based survey, 309 adults with self-reported ADHD, 309 adult family members of adults with ADHD, and 927 adults in the control population. Using an estimated 260, 120 adults with ADHD in Japan, the base-case analysis estimated annual medical costs at 74. 0 billion Japanese yen (JPY), social welfare costs at 389. 6 billion JPY, and productivity losses at 571. 1 billion JPY. Productivity losses in family members were estimated at 542. 2 billion JPY. Total socioeconomic burden was estimated at 1. 58 trillion JPY (~ US10. 9 billion) (~ 4 million JPY ~ US29, 000 per adult with ADHD). Social welfare costs and productivity losses increased with the number of comorbidities. In the scenario analyses, cost estimates varied from − 68. 9% to + 96. 1% relative to the base case and were most strongly affected by the method used to estimate the total number of adults with ADHD. This study, the first estimate of the annual socioeconomic burden of adult ADHD in Japan, underscores the necessity of more appropriate support for adult patients with ADHD and their families to reduce productivity losses. University hospital Medical Information Network Center (UMIN000051654; registered July 20, 2023).