Retention in Outpatient Psychological Treatment Services for Gambling: A Retrospective Cohort Analysis of Real-World Data Over a 10-Year Period

Abstract Retention is a persistent challenge in gambling treatment services, yet studies utilising real-world data remain scarce. This study examined rates, reasons, and predictors of treatment attendance using a large dataset ( n = 18,642) from outpatient gambling services in New Zealand (2014–2023). Out of every three clients in this study, one attended a single session (27.7%), one attended ‘multiple sessions’ (between two and five: 35.5%), and one attended a ‘longer course’ of six or more sessions (36.8%). Some clients attended single or multiple sessions as they had completed treatment (23.7%–38.8%), highlighting that lower attendance can reflect positive outcomes. Factors associated with single or multiple session attendance included younger age, male gender, lower perceived gambling control, and higher gambling expenditure, while greater problem gambling severity, depressive symptoms, and suicidality were associated with a longer treatment course. The findings underscore the need for tailored retention strategies, particularly early in treatment, such as brief motivational interventions.