Kengo Yokomitsu

Introduction In Japan, noriuchi refers to a collaborative gambling practice in which multiple players pool money used for betting and later split the final net profit or loss. This cross-sectional online study aimed (a) to estimate the prevalence of noriuchi among adult Japanese gamblers and (b) to examine how the frequency of noriuchi participation relates to gambling involvement and problem gambling severity. Methods In February 2022, an online survey was administered via Rakuten Insight, Inc. to adults aged 20 years or older. Participants were eligible if they reported gambling at least monthly in at least one of nine gambling activities during the past 12 months ( N = 2,000). Noriuchi participation frequency was assessed on a four-point scale (never, less than monthly, monthly or more, weekly or more). Outcomes included monthly gambling days, monthly gambling expenditure, and problem gambling severity measured with the Japanese version of the Problem Gambling Severity Index (PGSI). Results Overall, 498 participants (24.9%) reported noriuchi experience in the past 12 months; among them, 198 (39.76%) met the PGSI criterion for problem gambling. After adjustment for demographic covariates, noriuchi participation was associated with greater problem gambling severity across several gambling activities. Associations with monthly gambling days and expenditure were more limited and varied across gambling activities, with significant increases primarily observed among those engaging in noriuchi weekly for certain gambling activities. Discussion These findings suggest that noriuchi is associated with problem gambling severity, whereas its associations with gambling frequency and individual gambling expenditure are less consistent.