Initial development and psychometric properties of the Gambling Disorder Test in a nationally representative sample of adults.

Gambling disorder (GD) is an officially recognized mental health disorder. However, its conceptualization and diagnostic criteria have changed substantially over the years due to new clinical and epidemiological research supporting its reconceptualization from an impulse control disorder to an addictive disorder. The evolving nature of GD led to changes in its diagnostic approach within the 11^th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-11). However, no updated standardized psychometric test reflecting the latest developments exists. Therefore, the goal of the present study was to develop and report the psychometric properties of the Gambling Disorder Test (GDT), a brief and convenient four-item assessment instrument reflecting the current diagnostic criteria for GD in the ICD-11. A nationally representative sample of British adults was recruited (N = 1,028, M_age = 46.54 years, SD_age = 15.71). The results showed a one-factor solution for the GDT and initial support for the scale's factorial validity, population cross-validity, criterion validity, concurrent validity, and reliability. Further gender-based measurement invariance was conducted, with the GDT exhibiting full scalar invariance and the results of latent mean comparison showing that males had significantly higher GD latent means compared to females (latent mean difference = -0.156; z = -3.844, p < .001, d = -.249). The self-reported prevalence of GD in the sample was 0.49%. The GDT is a promising brief assessment instrument based on the latest conceptualization and diagnostic criteria for GD that can be employed by clinicians and researchers alike. (PsycInfo Database Record (c) 2025 APA, all rights reserved).