Evidence-based Measurement of Gambling Disorder: A Review of Instruments for Different Purposes.

Gambling Disorder is a significant public health and clinical issue requiring precise and reliable measurement instruments for effective screening, assessment, diagnosis, and treatment outcome evaluation. This narrative review, incorporating a realist rapid review phase, examined and categorised measurement instruments for Gambling Disorder in adults, distinguishing their uses and appropriate contexts to provide practical guidance for clinicians, researchers, commissioners, and policy-makers. We conducted searches across PubMed, PsycInfo, Scopus, Medline, and Google Scholar, focusing on peer-reviewed studies that evaluated psychometric properties, diagnostic accuracy, and/or practical application of Gambling Disorder measurement instruments. Findings were categorised as relating to screening, diagnosis, or treatment outcome (for the latter including symptom severity, processes/mechanisms, and recovery). We identified a range of instruments developed for different purposes and validated in diverse contexts, including brief and extensive screening instruments, diagnostic interviews, and measures of treatment response. The review highlights key considerations for instrument selection: sensitivity and specificity vary substantially across different settings (general population versus enriched clinical samples), with implications for prevalence estimation and clinical decision-making. We provide evidence-based recommendations for optimal instrument choice in specific contexts, including for: quantification of prevalence in the general population, screening in enriched settings (e.g. certain types of outpatient clinic), diagnosis, severity and treatment response. The review also identifies critical knowledge and methodological gaps, including limited validation across diverse populations and lack of gold-standard comparisons, which should be addressed in future work.