The relationship between physical availability of gambling and gambling behaviour or gambling disorder: A systematic review

Although it is often regarded as obvious, the exact nature of the relationship between gambling availability and gambling behaviour or disordered gambling remains unclear. However, disordered gambling is an important public health issue and restrictions on availability are seen as an important strategy to reduce gambling- related problems in many jurisdictions. Applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we reviewed studies on the relationship between physical gambling availability and gambling behaviour, as well as disordered gambling, and focused on several currently discussed hypotheses about their relationship. We used a systematic electronic search strategy involving 12 search terms and several databases. We included 27 studies and evaluated them by applying a comprehensive quality rating and quality weighting of evidence. We found a high proportion of quality-weighted evidence for both a positive relationship (access hypothesis) and a decrease or plateau in the prevalence of gambling participation and disorders over time with increasing availability (adaptation hypothesis). However, several conceptual and methodological problems hamper final conclusions. For example, studies were often not based on precise hypotheses, only two studies had a longitudinal design, overall quality ratings varied widely, operationalizations of gambling availability were sometimes not objectively measured, follow-up periods were insufficient, and shifting behaviour was not assessed. To understand the causal role of gambling availability in the development and course of gambling disorder and to derive evidence-based prevention strategies, investigators need to perform more high-quality longitudinal research that is based on a solid theoretical framework with the corresponding statistical analyses.