Video games have undergone substantial evolution since their integration with internet-based platforms, with a notable shift being the monetization of virtual items through chance-based activities [1]. Among the most widely debated mechanics is the “loot box” system [2]. This system permits players to purchase boxes containing randomized items of varying rarity, functionality, and monetary value. Highly coveted items, which enhance gameplay or provide unique aesthetic modifications, are often accessible exclusively through loot boxes [2,3]. Although the concept of probabilistic rewards for in-game items has been a feature of video games since the early days of role-playing games, it is evident that such mechanics have become increasingly monetized by capitalizing on the psychological loop between probability and instant gratification [4].

In addition to loot boxes, numerous games have implemented other forms of microtransactions, including downloadable content, purchasable upgrades, and play passes, which can be acquired with real-world money or via intermediary in-game currencies [2,5]. The gambling-like features (GLFs) of video games have expanded to include both players and spectators, notably through “skin betting” and esports wagering. Esports, much as traditional sports, now allow spectators to place bets on teams and players [6], with websites emerging that facilitate match tracking and performance analysis (eg, Oddspedia). A survey conducted in the United Kingdom revealed that 8.5% of adults had engaged in betting on esports [7], while an Australian study found that 41.5% of respondents participated in esports cash betting, skin betting, or skin gambling [8]. Other platforms have broadened the scope of betting to include not only professional esports leagues but also everyday matches involving skilled players, with transactions occurring in both real-world currency and virtual items or skins, the latter referred to as “skin betting.”

The ICD-11 (International Classification of Diseases, 11th Revision) recently classified gaming and gambling disorders as conditions related to addictive behaviors, underscoring shared diagnostic criteria and symptomatology [9]. Global data indicate a past-year prevalence of gambling disorder ranging from 0.12% to 5.8% [10], while the prevalence of gaming disorder stands at approximately 3.3% [11]. Prior research has estimated the comorbidity between gaming and gambling disorders at approximately 15%. Moreover, emerging evidence has suggested a potential “gateway” effect, where individuals transition from gaming to gambling disorder [12,13]. However, contemporary discourse in this nascent field has shifted toward examining the underlying motivations that drive the initiation and persistence of the transition between the two disorders. It is also plausible that certain gamer populations are more frequently sensitized to gambling stimuli, partly due to the proliferation of targeted gambling advertisements—similar to those promoting other addictive substances [14] and particularly within Southeast Asia [15]. This sensitization places vulnerable adolescents and young adults at elevated risk for problematic gambling behaviors [16]. The increasingly aggressive nature of gambling advertisements, coupled with inadequate regulatory oversight, exacerbates this issue. The paucity of clinical evidence, particularly concerning the gateway effect, presents therapeutic challenges and underscores the urgent need for further research [17].

This study seeks to explore the forms of intersection between gaming and gambling disorders. To achieve this, we conducted a scoping review to systematically evaluate the existing evidence on the overlap between gaming and gambling disorders. The scoping review method was selected, as it offers an exploratory overview of the available literature [18], allowing for the identification of gaps in research. Our scoping review attempts to focus on the gateway effect, while also examining other associations, that is, embedded gambling mechanics within digital games and the clinical comorbidity between the two disorders.

This scoping review aimed to examine the existing body of literature, map the landscape of available publications, and analyze selected evidence. A specific relationship, known as the “gateway effect,” describes the transition from gaming to gambling disorders [107]. Our findings indicate an increase in studies seeking to clarify this relationship, highlighting the clinical challenges posed by the convergence of gaming and gambling platforms. This overlap potentially heightens awareness of the gateway relationship, leading to increased reports and complex analyses. Overall, the pooled data suggest a small to moderate correlation between gaming and gambling behaviors [108]. However, much of the evidence supporting the gateway effect is derived from cross-sectional studies, limiting causal inference. Additionally, studies varied widely in defining initial pathological gaming behaviors and subsequent problematic gambling activity [8,27,28,53,63,68,69,75,76,92,94,109-111]. For instance, Vadlin et al [53] assessed predictive gaming behaviors using the Gaming Addiction Identification Test, whereas Molde et al [27] used the Gaming Addiction Scale. Exposure to GLFs in nongambling environments may also acclimate individuals to gambling [61,112]. Some recent studies have failed to replicate significant associations between in-game gambling activities (ie, loot boxes) and problematic gambling [46-48]. More nuanced analyses suggest that the association between loot box engagement and problematic gambling may be indirect, driven by gambling-related cognitive biases [47]. In addition, Xiao et al [46] propose that cultural factors, such as limited gambling availability and enforced transparency within the gambling industry, may contribute to the nonsignificant association observed in their Chinese-speaking sample.

Although estimates exist for gaming-gambling comorbidity, the rates of transition via the gateway effect remain unclear. Moreover, despite global reports of higher rates of gaming disorder [113], there is limited data from Asian countries on gaming-gambling convergence. In Indonesia, all forms of gambling, including loot boxes, are prohibited [32], which may contribute to a societal stigma surrounding such behaviors and thus related research. Additionally, Southeast Asian countries tend to prioritize enforcement measures, such as crackdowns on gambling [114], rather than investing in public health research on gambling [115]. In Indonesia, gambling and other behavioral addictions are not covered by the national health insurance system, further contributing to the scarcity of data and limited research in this area. Nonetheless, there has been a recent rise in empirical studies from Indonesia examining gambling elements within online video games [30,31]. The Lancet Public Health Commission’s [116] initiative on global cooperation to address boundary-crossing gambling products should encourage research in Global South countries, such as Indonesia. Enhanced empirical evidence is essential for informing policies in these regions, as unique national gambling cultures [46] and differing jurisdictions [117] have been shown to influence gaming-gambling convergence in various ways.

Some experts suggest that legal age attainment may amplify gambling participation [118], though this factor is inapplicable in countries where gambling is prohibited, such as Indonesia. Additionally, the gateway transition may be encouraged by increased economic access (eg, loans or buy-now-pay-later options [119]) upon reaching adulthood. Furthermore, the transitional mechanism may be reinforced by exposure to gambling advertisements [54]. However, such exposure and initial GLF involvement do not necessarily lead to problematic gambling behaviors. Multiple studies have indicated that additional biopsychosocial vulnerabilities (eg, gambling-related cognitive fallacies) are required for these behaviors to develop [47,48]. Preliminary findings indicate that certain biopsychosocial factors in the gateway effect mirror elements of the Interaction of Person-Affect-Cognition-Execution model [120], which describes risk factors for gaming and gambling disorders independently. These factors include younger age, specific temperamental traits, and impaired cognitive processes. Notably, the evidence linking sex to the gateway effect has become increasingly ambiguous. Female participation in video games and GLFs has been steadily rising [67], which corresponds with a heightened risk of problematic gambling among this demographic. Some researchers propose that this trend may resemble the telescoping phenomenon observed in gambling disorders, where the onset and progression of gambling-related issues occur more rapidly [55]. Concurrently, online gambling advertisements have increasingly targeted female audiences [121]. There is evidence of shared neurobiological disruptions to the prefrontal cortices and striatum, particularly within the default mode and reward circuits, in both gaming and gambling disorders [122]. However, definitive data linking these neural alterations to the gateway effect are still lacking.

Several identified studies also observed that the reverse effect (gambling to gaming) was not statistically significant [27,109,123]. This phenomenon raised the question of whether gambling has higher addictive potency than gaming. Some gamblers engage in video game chance-based activities as they are perceived to be “safer” [28]. Prior gambling participation did correlate to higher microtransaction involvement [124-126]. Moreover, several studies [52,54,82] have discovered the associative link between gambling marketing around video games to gambling behavior, though modest, and gambling industries have used these targeted advertisements to expand microtransactions (eg, loot box) usage [127].

These patterns might be sensitized with prior engagement to chance-based activities in-game and exposure to gambling advertisements. The two elements might represent a dual-hit pathway for the gateway transition mechanism, similar to the two-hit hypothesis of schizophrenia [128,129] that proposes genetic factors (first hit) sensitize an individual to the environmental insults (second hit) leading to schizophrenia. Adopting the concept, the in-game or peripheral participation in gambling-like activities primes the individual as the first hit, and the gambling advertisements act as the second insult leading to real-world gambling participation (see Figure 3; note that the figure is not meant to be exhaustive). An alternative pathway is presented that might circumvent the dual hit pathway, meaning only one of the two hits is experienced. For instance, the individual progresses from microtransactions to monetary gambling without exposure to gambling advertisements. The proposed dual hit pathway remains a hypothetical and theoretical model requiring empirical evidence to demonstrate if it poses a greater risk than the other pathway.

Consequently, the response to mitigate the migration to gambling behaviors and the associated harms has been insufficient. The rapid evolution of gaming and gambling mechanisms on digital platforms has outpaced regulatory efforts. Historical policy experiences indicate that outright bans may not be the most effective solution [105,127]. Emerging blended forms, such as cryptogames, may also introduce new legal challenges. Instead, industry and structural strategies could encompass implementing more stringent age restrictions [130], restricting API access by third-party platforms [131], instituting additional licensing requirements [104], and promoting self-regulation and ethical conduct within the industry [132]. In 2016, Indonesia introduced its game rating system, which permits gambling-like elements in games rated for players aged 13 years and older, provided they do not include cashing-out features. However, the age threshold should be raised to 18 years, as gambling-like elements present risks and are illegal in the physical realm. Despite the recent increase in research on the gateway effect from gaming to gambling, there remains a significant lack of empirical, clinical, and psychological preventive measures. Early detection should be implemented for all patients with gaming disorder by screening for involvement in microtransactions and other gambling-like activities. This approach will facilitate the application of harm reduction strategies, such as limiting access to real-world money and restricting transactions to virtual currencies that cannot be cashed out. Additionally, engaging families or significant others in the use of supervision applications can help restrict exposure to gambling advertisements. More targeted interventions should focus on clinical management to address cognitive biases and gambling fallacies, fostering awareness that chance-based activities constitute gambling and may have negative consequences.

Overall, the existing studies illustrate that children, adolescents, and emerging adults are particularly vulnerable to the convergence of gaming and gambling. Additional predisposing factors contributing to the transition toward risky behaviors in these groups, such as high impulsivity and sensation-seeking tendencies [76,133], warrant further research. Moreover, additional research is needed to substantiate the gateway effect, aligning with the perspectives presented in previous reviews and commentaries [17,25,107]. Most studies on the gateway effect have focused on traditional Western gambling activities, leaving region-specific gambling activities, such as pachinko in Japan or karambol in Indonesia, relatively underexplored. Further research is essential to clarify the epidemiology, specific mechanisms of transition, directionality of the transition, definitive risk factors, and effective preventive measures related to the gaming-gambling gateway effect.

This study has several limitations. First, the scoping review approach lacks the comprehensiveness of a systematic review, and the identified publications are not exhaustive (for instance, preprint databases were not included, and the search strategy was not preregistered). Consequently, the descriptive counts and proportions presented here reflect only the exploratory sample of identified publications, not the entire body of literature [18]. Second, this study did not address gamified gambling or the growing trend of skill-based gambling forms. Publications focusing solely on social casino gambling were also excluded, as these are traditional gambling activities delivered via the internet rather than video games [107]. Third, this scoping review incorporates some viewpoints and commentary pieces to map the publication landscape. Where feasible, references to these sources have been minimized or clearly identified. Readers are encouraged to be mindful of the varying levels of evidence these pieces provide and to refer to the supplementary materials or reference list for verification if needed. Fourth, the majority of empirical studies rely on self-reported data, which may impact accuracy and necessitates caution in interpretation. Finally, studies that compare gaming and gambling through distinct or combined samples, or with differing diagnostic criteria, were excluded, as such heterogeneity does not support direct examination of overlap or convergence. Nonetheless, these studies still offer valuable insights into the broader relationship between gaming and gambling disorders as behavioral addictions.