Legal and regulatory responses to online gambling harms: a scoping review of evidence

Abstract

Objective

To synthesise original research on the distinct challenges of regulating the online sector, and the efficacy of public health legal interventions aimed at reducing online gambling harm.

Background

Both legal and public health scholars increasingly view gambling as a public health concern. Gambling puts individuals at risk of a range of harms, including related to finances, relationships, mental health, physical health, employment/education, and criminal activity. Harmful gambling can extend beyond the realms of individual harm to affect others including wider society. Online gambling is growing in many countries—e.g. it accounts for 44% of gambling turnover in the UK—and it is seen as especially harmful compared to land-based gambling due to the accessibility, and fast-paced nature of the products available. In addition, there are distinct harms associated with the overlap between gaming and gambling, most prominently through the challenges that exist in the regulation of loot boxes. Legal and public health scholars recommend legal interventions to reduce the harms of gambling, including online gambling.

Methods

Following a PICOST inclusion/exclusion criteria, we completed a comprehensive scoping review of scientific and legal data sources to ascertain the efficacy of legal interventions on reducing online gambling harms. A narrative synthesis of the included studies was completed.

Results

We include 27 data sources which either described distinct challenges of regulating online gambling or evaluated the efficacy of laws and regulations. Current gambling harm reduction research is heavily focused on using an individual approach, rather than a systems approach. When a systems approach is taken, it often prioritises tackling unlicensed gambling and blocking mechanics, which require a comprehensive delivery strategy to be effective. Significant gaps exist in examining the effectiveness of interventions on subgroups of the population.

Conclusions

Inadequate legal and regulatory frameworks have played a crucial role in the proliferation of online gambling harms; studies vary in their explanation for this inadequacy. There is an urgent need for more robust research on law, regulation, and online gambling harms to critically explore the implications of technology, ongoing innovation, and the intervention generated inequalities of regulating online gambling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12954-025-01292-y.

Context/background

Concern about gambling harm has grown in several countries, from Germany to Australia, Canada to China. This concern has often been fuelled by escalating evidence of harm stemming from liberalisation of gambling. For example, when the 2005 Gambling Act came into effect in 2007—significantly liberalising commercial gambling operations in Great Britain—regulation was largely focused on enabling growth. Gambling was viewed as economically positive, generating tax revenue, and jobs. Indeed, after paying out winnings, licensed gambling operators retained over £15 billion from their UK operations last year [1]. However, as profits have grown, so too have concerns about harm.

Harmful gambling is extensively evidenced as directly and indirectly harmful to physical and mental health, and is associated with addiction, mental health problems, financial distress, family disruption and even homelessness and suicide [2, 3]. Marionneau and colleagues have characterised gambling harms into seven themes: (1) financial, (2) relationship/conflict, (3) emotional and psychological (mental health), (4) health decrements (physical health), (5) employment/ education, (6) cultural, and (7) criminal activity [3, 4]. Harmful gambling can extend beyond the realms of individual harm to affect friends, family, the community and wider society [5–7]. The UK’s Office for Health Improvement and Disparities (OHID) estimate harmful gambling to cost around £1.05–£1.77 billion annually in England alone.

The distinct harms of online gambling

Online gambling has exploded in popularity around the world. For example, it now accounts for 44% of gambling turnover in the UK—£6.9 of £15.6 billion [1], while total wagers on Ontario’s online gaming platform increased 31% between 2023–4 and 2024–5 (to CAN $82.7 billion) [8]. This exponential growth in the online gambling market has changed gambling experiences [9–12]. Online products are designed to be rapid and intensive with continuous-play format gambling products having the strongest association with harmful gambling in terms of prevalence and effect size [13]. Platforms offer an extensive selection of products, accessible 24/7, and without the sociable element of some land-based gambling experiences [9–12]. These features are all associated with higher risks of gambling harm.

The rapid expansion of the online market has increased the number of individuals at risk of gambling harms [3, 14]. Multiple studies confirm that rates of problem gambling, harmful gambling, and at-risk gambling are higher for online gambling than for most types of in-premise gambling [15–19]. In the UK at-risk gamblers are more likely to gamble online (23.4%) compared to the general population (9.4%) [20].

Loot boxes

Research on online gambling also identifies a distinct set of harms related to the gamblification of gaming, primarily through microtransactions using mechanisms such as loot boxes and ‘Gacha’ games. These involve a randomisation of rewards and expenditure of real-world money. Hence many argue that they share features of gambling, and that game players are impacted by potential harms [21, 22]. The association between loot box spending and harmful gambling ehavior has been confirmed in research [23]. It has been estimated that 5% of loot box spenders produce over half of loot box revenue [24], suggesting that there is significant potential for individuals to experience financial harms from engaging in loot boxes. Moreover, Zendle and Cairns [25] found that those with the greatest severity of gambling harm spent more money on loot boxes, with similar findings replicated across adolescents [26] and the general population [27], in a host of European countries [28–30], North America [22, 31], Australia and New Zealand [22, 32], and in mainland China [33]. Furthermore, use of loot boxes among adolescents has been reported to be associated with gambling frequency [34, 35] and seeking out gambling activities [36].

Legal and regulatory intervention as a harm reduction tool

Experts who advocate for a public health approach to gambling—online and land-based—regularly identify a need for improved legal and regulatory interventions [14, 37–40]. Such interventions aim to reduce harmful gambling by reducing availability and accessibility, such as by restricting the types of games played or amounts wagered, [41], enabling exclusion from marketing and/or playing, holding companies liable for harms caused from negligent operations, mandating better cooperation with, and signposting to, support services, and increasing the financial obligations placed on industry to pay the full social costs of their activities.

Justification for a review of the evidence

These legal and regulatory interventions obviously require evaluation. In this regard the British gambling regulator, the Gambling Commission, [42] calls for a better evidence base for gambling regulation in its 2023–6 plan. However, researchers have voiced concerns about the lack of robust evaluation of legal interventions, and the need to tackle conflicts of interest stemming from industry involvement in intervention evaluation [14, 37, 39, 43].

As with all public health interventions, then, laws intended to improve public health outcomes must be properly assessed for their effectiveness, including their potential unintended consequences [44]. To facilitate effective interventional public health laws and regulations to address online gambling harm specifically, lawmakers need researchers to review relevant evidence about what works, for whom, and what the positive and negative effects [45] of specific laws and regulations may be. Negative effects may include paradoxical effects (e.g. interventions aiming to reduce gambling that appear to increase it), and harmful externalities (e.g. psychological harms, or equity harms) [45, 46].

Research outside gambling has shown that health inequities and inequalities may be generated by legal frameworks intended to improve public health [47–49]. Health equity and equality, although linked concepts, refer to different aspects of fairness in healthcare access and experiences. Health equity refers to fairness and justice in healthcare, providing what individuals need to be healthy, whereas health equality refers to providing the same resources to everyone [50]. To mitigate the risks of intervention generated inequalities (IGI), particular attention to sub-groups of populations is needed to establish individual and intersectional effects of interventions, whether positive or negative [44]. Currently, young adults, and men, are most commonly identified as at-risk sub-groups for online gambling harms in the evidence base [14, 51, 52]. Assessing the evidence base in a more intersectional way is recommended to improve research quality and ensure robust intervention effects [53].

To our knowledge, there is no research which synthesises evidence on the distinct challenges of regulating the online sector, and the effects of legal and regulatory interventions intended to reduce online gambling harms (including on different subgroups). Given the recent developments in the evidence- base and calls from both legal and public health scholars to improve the efficacy of laws and regulations to reduce gambling harms, we undertook a scoping review to identify and summarise the current global evidence-base for online gambling harm reduction law and regulation.

Methods

The primary aim of our scoping review was to identify, map, and synthesise evidence on the effects of legal interventions intended to reduce online gambling harms, by utilising a comprehensive search strategy, drawing on diverse bodies of evidence, including diverse stakeholder perspectives, and accounting for the breadth of intended/unintended and spillover effects to capture their impact [54–56]. A secondary outcome was to identify, map and synthesise evidence that describes the specific challenges related to legal interventions intended to reduce online gambling harms.

A comprehensive search strategy was critical for this scoping review as previous efforts to synthesise evidence about online gambling harms have been restrictive by excluding important sources from outside of medical databases, and failing to account for sub-group specific differences in efficacy [57–59].

Hence, to ensure breadth in our included data sources, we employed an interdisciplinary approach to search strategy development. Our team consists of legal and public health experts who collectively developed and refined the search strategy and database selection, alongside patient and public involvement (PPI). Additionally, to ensure we included an equity lens to our review, we also committed to identifying, mapping and synthesising evidence on the subgroups of populations where practicable.

Study design

This scoping review is nested within an existing systematic review and follows the PRISMA Sc-R reporting guidance for scoping reviews [60]. A protocol was not developed for this review, however a protocol has been published for the wider review [61]. We extracted a subset of online gambling harm reduction evidence from our primary systematic review (ongoing). We made one adaptation to the primary review, to add in a further filtering step to capture interventions pertaining to online gambling by applying the intervention filters of ‘online’ or ‘gaming’ or ‘internet’. Citation and hand searches augmented the initial database search. The inclusion criteria can be seen in Table 1.

Table 1.

Population, Intervention, Comparator, Outcome, Study design, Timing (PICOST) inclusion criteria

Subject	Concept
Population	Any study describing any global human population or sub-population
Intervention	Interventional public health laws and regulations intended to reduce the harms associated with online gambling Interventions can be single component or part of a multi-component package, as well as universal, selective (e.g. access restrictions targeting young adults), or indicated (e.g. mandated affordability monitoring informed by demographic and individual risk profiles)
Comparator	None
Outcome	(1) Health and health equity outcomes, for gamblers and affected others (e.g. family, friends). For example:  Reduced Problem Gambling Severity Index score  Reduced gambling spend and/or reported financial harm  Mental distress, depression, anxiety, and negative emotional consequences  Negative behavioural consequences including criminal behaviour  Relationship happiness, relationship assessment (2) Outcomes by subgroups in the general population (PROGRESS-PLUS categories [58]) to allow us to assess for any inequity generated impacts of a legal/regulatory intervention within a jurisdiction (3) Measures of compliance and enforcement (4) Cost effectiveness (5) Positive, negative and spillover effects (including economic costs, paradoxical effects and harmful externalities, including widened health inequalities)
Study design	(1) Randomised and non-randomised controlled trials (RCTs) (2) Prospective and retrospective cohort studies (3) Controlled before-and-after studies, including econometric studies, interrupted time series studies, and regulatory impact studies (4) Observational studies, meta-analyses, modelling studies (5) Impact, process, and economic evaluations (both cost benefit analysis and cost effectiveness analysis) (6) Studies that seek to relate intervention costs and savings to health and wellbeing outcomes or benefits (7) Studies of moral hazard (a key law and economics framework for discussing unintended consequences)  (i) Any qualitative studies of the health equity effects of relevant legal interventions
Timeframe	(1) All databases searched from date of inception to August/September 2024

Identifying the relevant studies

As detailed below in Table 2, a search strategy was developed by an information specialist (JK) and database searches were completed in August/September 2024 for the primary systematic review.

Table 2.

Example search strategy exported from Medline

#	Query	Results from 27 Aug 2024
1	GAMBLING/	7,236
2	gambling.ti,ab,kw	10,030
3	(gambler or gamblers).ti,ab	2,907
4	(gamble not standard gamble).ti,ab,kw	1,473
5	(betting or bettor* or wager*).ti,ab	1,155
6	((bets or bet) not (“bet hedging” or hedge* or inhibitor* or inhibition or T Bet or proteins)).ti	1,782
7	(bingo or lottery or lotteries).ti	674
8	((gaming or slot or fruit or poker or lottery or lotteries) adj5 (machine* or terminal*)).ti,ab	930
9	((game or games or gaming or gamer?) adj5 (money or monetization or monetisation or monetary)).ti,ab	260
10	(lootbox or loot box or lootcrate or loot crate or game credit or microtransaction or in game purchase).ti,ab	53
11	(Casino* or cashino* or bookmaker* or book maker* or bookie* or amusement arcade*).ti,ab	764
12	1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 or 10 or 11	15,431
13	Gambling/pc [Prevention & Control]	226
14	Legislation as Topic/	16,025
15	Legislation & Jurisprudence.fs	262,722
16	Licensure/	7,557
17	Government Regulation/	21,953
18	(legislat* or statutory or legal* or law or laws or mandat* or ban or banning or bans or prohibit* or reform* or prohibit* or licences or licencing or licenced or jurisprudence or ordinance or forbid* or interdict*).ti,ab	469,980
19	(act or acts or restrict* or code or requirement).ti	128,438
20	((regulation* or regulatory or regulate*) not (emotion* adj2 regul*)).ti	516,133
21	(statutory adj2 (code* or regulation*)).ab	219
22	(regulatory adj2 (authorit* or approach* or change* or reform*)).ti,ab	10,069
23	(gambling adj2 (board* or regulat* or commission* or authorit*)).ti,ab	120
24	(Lawmaker* or law maker* or government* or police).ti,ab	176,455
25	(Compliant or compliance or enforce* or sanction* or prosecution* or deregulation).ti,ab	229,725
26	14 or 15 or 16 or 17 or 18 or 19 or 20 or 21 or 22 or 23 or 24 or 25	1,619,960
27	*Public Health/	58,511
28	*Harm reduction/	2,030
29	exp *Government/	46,144
30	exp *policy/	106,837
31	(Harm* adj2 (consumer* or minimi?* or prevent* or reduc*)).ti,ab,kw	17,925
32	(health adj2 (ministr* or department*)).ti,ab	51,768
33	“public health”.ti,ab,kw	386,723
34	(policy or policies or intervention* or program* or measures or postpolicy or prepolicy or policymaker* or policy maker*).ti,kw	628,523
35	((debt* or relationship* or crime*) adj3 (intervention* or program*)).ab	3,635
36	27 or 28 or 29 or 30 or 31 or 32 or 33 or 34 or 35	1,156,325
37	*Social Responsibility/	8,134
38	*Reminder Systems/	2,315
39	(Reduction adj1 (demand or supply or opportunity or access)).ti,ab	462
40	consumer protection.ti,ab,kw	925
41	(Protect* adj2 (play* or behavio?r)).ti,ab	10,687
42	(responsib* adj1 social*).ti,kw	1,266
43	((stake* or spending or loss or price or monetary or time or deposit) adj2 (limit* or maximum or capping or restriction)).ti,ab	33,284
44	Persuasive design.ti,ab	50
45	(Messag* or warning or pause* or break*).ti	73,592
46	((messag* or banner) adj1 (static or dynamic or pop-up or safer or warning or health or intervention or responsib*)).ti,ab	5,497
47	(Advertising or marketing or sponsorship*).ti	14,955
48	(watershed or pre-watershed).ti,ab	12,359
49	(feedback adj1 (behavio?r or personalis?*)).ti,ab	241
50	(risk rating or play tracking or play scan or playscan or cashless or card based or acceptor* or pre commitment or precommitment or affordability check* or self exclusion or self appraisal or break play).ti,ab	74,522
51	(age adj1 (limit* or legal or minimum)).ti,ab	4,577
52	(limit or limits or limiting).ti	45,715
53	37 or 38 or 39 or 40 or 41 or 42 or 43 or 44 or 45 or 46 or 47 or 48 or 49 or 50 or 51 or 52	283,811
54	26 or 36 or 53	2,848,828
55	12 and 54	2,548
56	13 or 55	2,625

Search strategy

The search utilised a broad range of databases reflecting the multidisciplinary nature of the topic and included the following databases; CDC’s Task Force on Community Preventive Services (Community Guide); Health Evidence database (Canada); MEDLINE, Embase, CINAHL, PsycINFO, Social Policy and Practice (OvidSP); Cochrane Database of Systematic Reviews (CDSR) and the Cochrane Central Register of Controlled Trials (CENTRAL); NHS Economic Evaluation Database (via the Centre for Reviews and Dissemination); Social Science Citation Index and Conference Proceedings Citation Index (Web of Science, Clarivate Analytics); EconLit, Criminal Justice Abstracts (EBSCOhost); Westlaw; Heinonline; Scopus; ProQuest Dissertations & Theses Global, Sociological Abstracts including Social Services Abstracts (ProQuest); Trials Register of Promoting Health Interventions (TRoPHI) and Bibliomap (EPPI-Centre); Campbell Systematic Reviews (Campbell Collaboration).

To identify the subset of evidence related specifically to online gambling, a further scoping search applying filters to intervention terms was completed in December 2024. All data sources relating to online gambling harm reduction were filtered out of the primary search results within the Covidence reference management software using key filter terms ‘online’ OR ‘internet’ OR ‘gaming’ and screened for relevance. From the initial pool of results, this scoping exercise narrowed the results for screening to 4,144 data sources (see Fig. 1 PRISMA flow chart for more details). This secondary search was augmented by hand searches and citation searches.

Fig. 1.

PRISMA flow chart (According to Moher et al. [62])

Study selection process

We included all primary research articles, research protocols, review articles and book chapters that evaluated legal interventions for online gambling harm reduction. Material published in the form of commentaries, editorials, letters to the editor, conference abstracts, and opinion pieces were excluded. Data sources were screened in the Covidence software, exported to EndNote, and key outcomes annotated.

Data synthesis

Included studies were heterogeneous and hence we undertook a narrative synthesis. Following the PRISMA Sc-R guidelines [60] included evidence was not formally critically appraised as this is not a requirement [63].

Results

Descriptive results

A total of 27 data sources were included in this scoping review (see Table 3 below), covering gambling regulations in Great Britain [11, 19, 64–68], elsewhere in Europe [69–77], North America [12, 13, 78, 79], Australia and New Zealand [9, 10, 80], People’s Republic of China [81] and studies in multiple jurisdictions comparative to the regions mentioned above [40, 82, 83]. The types of research included are surveys [12, 69–72, 75, 76, 79], qualitative studies [10, 66, 80], legislative/policy analysis [9, 19, 64, 65, 67, 74, 77, 78, 81], reports [68], and review pieces [11, 13, 40, 82, 83].

Table 3.

Eligible article characteristics

Data sources reporting challenges of regulating online gambling harms
First author and year	Location of study	Study design	Study concept	Evaluation
Allami [13]	Canada	Meta-analysis	Gambling harm prevalence	Continuous-play format gambling products have the strongest association with harmful gambling
Bedford [64]	UK	Qualitative legal analysis	a. Online advertising b. Regulation development	a. Affiliate marketing offers little consumer protection b. Legislative changes to accommodate wider definitions of gambling to increase variety online gambling products
Hing [9]	Australia	Qualitative legal analysis	Regulation for gambling harm reduction	Characteristics of online gambling as a challenge for regulation
Hing 2015 [10]	Australia	Qualitative study	Gamblers experience of internet gambling and regulation	Characteristics of online gambling as a challenge for regulation
Hornle [65]	UK	Analysis of advertising practices	Online advertising	User-generated content and social media provide loopholes for advertisement of gambling
Lakew 2024 [66]	UK	Qualitative study Exploratory focus group	Payment systems	Digital payment systems can increase risk of harm by making it easier to play and pay
McCormack [11]	UK	Scoping review	Online gambling characteristics	Characteristics of online gambling as a challenge for regulation
Newall [19]	UK	Qualitative legal analysis	Player tracking	Characteristics of online games as a challenge for regulation
Wood et al. [12]	Canada	Survey	Gambler characteristics	Characteristics of online games as a challenge for regulation
Xiao [74]	Belgium	Prevalence and content analysis	Enforcement	Belgian ban on loot boxes is not effectively enforced
Xiao [81]	People’s Republic of China	Prevalence and content analysis	Compliance	Suboptimal compliance with loot box legislation
Zborowska [67]	UK	Qualitative legal analysis	Regulation development	Regulators collaborated with the gambling industry to build the regulations

Data sources Reporting Efficacy of Law/Regulation
First author and year	Location of study	Jurisdiction	Law/regulation discussed	Study design	Study concept	Evaluation
Buil [77]	Spain	Spain	Law 13/2011 and RD 1613/2011 BOE Num 275 of 15 November 2011 art. 6.2	Legal analysis/evaluation	Age restrictions	Shortcomings in enforcement
Egerer [82]	Finland	Global	Multiple – See article for details	Review	Blocking measures	Lack of comprehensive implementation strategies
Engebo [69]	Norway	Norway	N/A	Longitudinal survey (N = 28,251 past-year gamblers)	Stronger online restrictions	Did not reduce the rates of offshore gambling
French [78]	Canada	Quebec	Loi sur la Société des loteries du Québec [Act respecting the Société des loteries du Québec], CQLR S-13.1	Situational analysis	Blocking measures	Individual level focus of legal framework is restrictive and narrow in definition of harm
Hakansson [71]	Sweden	Sweden	Spellagen [Gambling Act] SFS 2018:1138	Self-report survey (N = 619)	Mandatory self-exclusion measures	Individuals gambling in a harmful way more likely to seek out unlicensed opportunity
Hakansson [70]	Sweden	Sweden	Spellagen [Gambling Act] SFS 2018:1138	Repeated survey (N = 1,505)	Mandatory self-exclusion measures	Online gambling is the most common form of breaching
Hornle [72]	Europe	34 EU member states	Multiple—See article for details	European commission evaluation—survey	Blocking measures	Recommendations for comprehensive blocking packages
Hornle [68]	UK	UK	FCA, ‘The Principles’ PRIN 2.1 (FCA Handbook)	Mixed methods report	Blocking measures	Review of bank gambling blocks
Hume [80]	Australia	Australia	N/A	Qualitative perceptions of gambling (N = 175 young people)	Age restrictions	Age restrictions reduce access for underage gamblers but these rules can be easily bypassed
Kairouz [79]	Canada	Quebec	Loi sur la Société des loteries du Québec [Act respecting the Société des loteries du Québec], CQLR S-13.1	Cross-sectional surveys 2009 (N = 11,888) & 2012 (N = 12,008)	Blocking measures	Directing gamblers towards regulated did not reduce the prevalence of unlicensed gambling
Nordmyr [75]	Finland	Finland	1047/2001 Arpajaislaki [Lotteries Act]	Quantitative survey pre-post (N = 2,984 & 2,326 respectively)	Age restrictions	Prevalence rates of harmful gambling
Salonen [76]	Finland	Finland	1047/2001 Arpajaislaki [Lotteries Act]	Survey (N = 4,515)	Age restrictions	Prevalence rates of harmful gambling, lack of data for young people
Schmidt-Kessen 2019 [73]	Denmark	Europe	Multiple—See article for details	Legal design analysis	Blocking measures	Recommendations for effective landing page design
Shi [83]	Canada	Global	Multiple—See article for details	Review	Restrictions for young people	Age restrictions in online gambling should consider multiple populations including youth and young adults
Ukhova [40]	UK	Global	Multiple—See article for details	Review (25 jurisdictions)	Legislative trends	Global review of legislative trends

Published evidence in this domain fall in to two categories i. the distinct challenges of regulating online gambling [9–13, 19]; including advertising [64, 65], regulation of loot boxes in video games [74, 81], and legal frameworks [64, 67]—and ii. the efficacy of laws and regulations intended to reduce harm from online gambling; including regulatory changes [40], payment behaviours [66], effects of rules on the unlicensed sector [69–71], the impact of blocking measures [68, 72, 73, 78, 79, 82], and the impact of specific regulations on sub-groups of the population—namely age restrictions [75, 76, 80, 83] and advertising restrictions [77].

Narrative synthesis

The distinct challenges of regulating online gambling

There is widespread consensus that online gambling poses distinct challenges to law and regulation. For example, many major online gambling operators are located in small, offshore, no or low-tax jurisdictions, and/or they may offer their services across multiple borders. National regulators have long struggled to effectively control (or tax) such cross-border activity. Moreover, players can use anonymous payment methods (for example, bitcoin and other cryptocurrencies [84]), sidestepping payment blocking via formal banks. In addition, digital payment solutions (DPS) may facilitate harmful gambling because they enable faster and simpler transactions, including bypassing responsible gambling tools, and removing steps for depositing funds in to gambling accounts [66] and increasing the likelihood or intensity of play by ‘nudging’ or ‘triggering’ player activity which can increase risk of harm and normalise risky gambling habits (such as repeat top ups).

The increased risk of gambling harms in online play is explained in part by the 24/7 availability of online gambling, the anonymity of play, and the wide range of products hosted on platforms. Online, riskier types of gambling products (such as high stakes gambling machines, or casino-type games such as roulette) are often mixed with types of gambling that—offline—have a softer, slower, or more social feel (such as bingo). This has led to concerns that online gambling is exposing players to faster, more intensive forms of play [9–12, 19]. For example, in the UK online bingo operators can offer product mixes that are prohibited in licensed bingo premises, such as slots, roulette, and casino-style card games. The mechanics of online gambling are also designed to increase gambling spending, especially via in-play options for sports betting which generate time pressure to commit to a bet. Across the evidence base continuous-play format gambling products have the strongest association with harmful gambling in terms of prevalence and effect size [13]. These types of games make up a large proportion of online gambling sites. The removal of the in-person, social element of some land-based gambling experiences has also been understood to increase risk [9–12].

Challenges in regulating advertising

There are specific challenges associated with effective regulation of online gambling advertising, aligned to the wider failure to properly control social media platforms [65]. The commercial gambling industry has developed significant partnerships within social media platforms and professional sports industries to deliver online advertising [14]. Social media platforms are known to target gambling advertising to sub-groups such as younger people, and sports fans. There is limited regulation for automatic marketing opt-ins via social media platforms, meaning consumers are automatically opted in for advertisements typically with limited knowledge of the targeted nature, offering little consumer protection for at risk or problem gamblers. One study found that profitability in online bingo often depends on relentless affiliate marketing, including by sites that are advertised as player guides or consumer-oriented comparison aides but are being paid a share of revenues by websites [64]. In-game advertising is also common, with consumers exposed to targeted advertisements whilst accessing online gambling platforms which increase the likelihood of consumers seeking out different types of online play including riskier types of gambling. The digital footprint consumers leave behind is widely exploited for marketing.

User-generated content and peer to peer advertising across social media is another arena of challenge identified in the evidence base [65]. Blurred boundaries between editorial content and advertising enable the widespread promotion of gambling brands by influencers and comparison websites which can undermine consumer protection measures. Often blurring the boundaries of compliance with advertising regulations, user-generated content can enable interaction with at-risk and protected groups such as young people.

Challenges in regulating loot boxes

Jurisdictional variation in the definition of gambling results in significant disparities in the consumer protection measures available [85]. For example, the latest game in the multimedia franchise Pokémon, Pokémon Trading Card Game Pocket, is rated as 4 + in the UK, rated M (Mature) in Australia, but is unavailable for download in Belgium for its use of loot boxes. Assuming a law encompassing the gambling features of video games exists, there is a challenge of ensuring compliance. In one study, Xiao and colleagues [81] reported that in the People’s Republic of China, where it is mandated for companies to disclose the probabilities of each loot box items, there was sub-optimal compliance in the disclosure of probabilities of loot box items that is mandated by law. Although 95.6% of games contained probability disclosures, only 34.1% of games featured this information on both the in-game loot box purchase page and on the game’s official website. The authors concluded that most games failed to optimise their consumer protection efforts, not providing accessible information on loot box probabilities on multiple channels. Furthermore, the authors argued that this 95.6% figure should not be used as a measure of compliance with the law as many of the disclosures were inaccurate (e.g., probabilities adding up to more than or less than 100%). Another study reported that paid for loot boxes were available throughout a significant portion of the most popular Apple App Store games in Belgium [74]. Xiao [74] concluded the ‘ban’ on loot boxes had not been effective due to an insufficient enforcement of the law, demonstrated by findings that 80% of games still used a randomised monetisation method to generate revenue.

Legal and regulatory frameworks

For both advertising and the gamblification of video games, there is a general consensus that inadequate legal and regulatory frameworks have played a crucial role in the proliferation of online gambling harms. However, there are two distinct explanations for this inadequacy: as either primarily due to the challenge posed by rapidly evolving and innovative online gambling technologies, or as primarily due to the constitutive role of pro-innovation legal frameworks in enabling the growth of the online gambling sector. According to the first perspective, the challenge is lawmakers’ inability to respond fast enough to innovative new technologies. In short, the technology was ahead of the rules—innovators were ahead of the curve and regulators are still struggling to catch up. Law is understood to be lagging, or absent, in this understanding of the growth of online gambling harms. According to the second perspective, law co-constituted that growth. Studies in this vein explore the causal role played by the regulatory environment in the success of online gambling.

For example, an early study by Kingma and Zborowska [67] explored how Gibraltar became a key offshore hub for online gambling operations due to the collaborative work of regulators and the gambling industry in building the rules. Other studies of UK gambling have shown that the online sector was facilitated by a wider enthusiasm for e-commerce as the new frontier of growth, a low- or no-tax environment, and a pro-innovation approach to game definition which encouraged the industry to develop products—in premises and online—that permitted more intensive features [14, 86]; and that blurred boundaries between harder and softer forms of play, for example the redefinition of bingo which reduced the requirement for human participation [64]. Law was not absent, or lagging new technologies, in these examples. Rather, the cause for the inadequate framework was regulatory capture: the rules were being designed in the interests of industry growth, including due to a pro-innovation approach to new online gambling technologies.

This difference in explanation for the inadequacy of existing legal and regulatory frameworks for online gambling markets—as primarily due to law lagging new technologies or co-constituting those technologies—has profound implications for research and practice. While both sets of literature agree on the urgent need for improved controls, in the first scenario regulators have to catch up with cutting edge innovation, including by applying new technologies in their own work. In the second, they have to disentangle themselves from conflicts of interest that have inhibited their ability to robustly control the online gambling sector and its associated digital technologies.

The efficacy of legal and regulatory intervention for gambling harm reduction (including research gaps and priorities)

While the research we examined for this scoping review is relatively clear on the distinct challenges of regulating the online sector, there has been less work on i. the overall efficacy of laws and regulations intended to prevent or reduce these risks; ii. the health equity and equality impacts of those laws and regulations.

Robust and independent evaluations of the efficacy of laws and regulations intended to prevent or reduce harm

Several studies, across multiple jurisdictions, have demonstrated the inadequacy of voluntary or self-regulation approaches, such as non-binding good practice guidance [87–89]. These have long been the industry-preferred solution to gambling harm, and they have long been shown to be ineffective [37, 87, 90, 91].

Globally, current legal developments focus strongly on regulation of online gambling markets. A recent review examined global legislative changes in gambling harm across 25 jurisdictions between 2018 and 2021, which were sub-divided for analysis and included 19 regulatory changes for online gambling harm specifically [40]. This important review found that online gambling harm regulation continues to be framed predominantly at an individual-level, rather than systems-level. This consists of framing regulation under the umbrella of non-binding good practice guidance as opposed to broader regulation of gambling systems, such as website blocking. When developing regulations the types of gambling harms considered across the 25 jurisdictions were predominantly narrow, focused on problem gambling and addiction. This is an individual rather than industry or system focused approach to the cause of harms, and the primary targets for solutions. However, the data for this evaluation was taken directly from a database providing information to industry actors, highlighting another challenge with evidence in this field. The dataset could be missing vital regulatory approaches/narratives which are in the best interests of regulation that prevents or reduces harm, including efficacy for subgroups of populations.

There are fewer studies of the effects of hard laws (enforceable, legally binding, and with a clear legal obligation to comply) and regulations intended to reduce gambling harm. While many studies describe such laws, and the reasons behind their introduction, robust evaluations of their effects are less common. This is in part because such laws are often relatively recent, stemming from the aforementioned shift to a public health lens on gambling (Sect.  1). The studies that do demonstrate effects are largely focused on effects related to the unlicensed sector.

Impacts of stronger rules on the unlicensed sector

Some of the recent empirical evidence, although lagging, suggests that stronger rules for the licensed online market may have impacts on the unlicensed sector.

An empirical study examined the efficacy of two regulatory changes in Norway, firstly a slot machine ban in 2007 (a land-based regulation) and subsequently an introduction of regulated online interactive games in 2014 [69]. A survey of 28,251 past-year gamblers over a period of 2005–2018 highlighted that the introduction of regulated interactive games in 2014 had not reduced the rates of offshore gambling. The previous regulation restricting land-based slot machines (2007), also pushed more activity online.

In Sweden, additional deposit limit restrictions were enforced to regulate online gambling during Covid. A survey of 619 consumers showed that the regulation created an overall reduction in gambling prevalence post pandemic [71]. However, when focusing on the population of gamblers at risk of harm, 38.9% of gamblers at least moderate risk of harm reported a post-intervention decrease in gambling overall, but 42% reported an increase in online gambling post-intervention. This suggests that more consumers were directed towards online gambling as well as land-based gambling behaviours. In addition to this, 40% of participants reported gambling on other sites after reaching limits with the state monopoly.

Compared to the softer voluntary responsible gambling tools described above, Sweden operates a nationwide multi-operator self-exclusion service (Spelpaus) that is legally required for both online and land-based gambling sites. An updated survey of 1505 past-year gamblers has shown greater uptake of Spelpaus (9%) compared to previous years [71, 92], but greater breaching (49%), predominantly through online casinos (82%) [70].

Several studies also examine whether tightened rules may be directing consumers at risk of harms to unlicensed online gambling opportunities. Enforcing spending limits and self-exclusion practices are not facilitating less gambling for those at risk of harm in these instances, because there is a failure to simultaneously control the unlicensed sector. This suggests that a more comprehensive regulatory package may be necessary to prevent the industry from simply targeting areas of the market where lighter touch rules exist, in order to undercut protections within a jurisdiction. A key example of this is highlighted by Wardle and colleagues [93], who suggest that the industry mobilises narratives of black-market risks and unlicensed online gambling specifically to get the rules for online gambling softened. However, from a harm reduction perspective, the aim should be to both make the unlicensed market less accessible, and to more effectively regulate the licensed market.

Impact of blocking mechanisms to restrict unlicensed gambling

One response to reduce the risks of unlicensed gambling whilst also tightening controls on the regulated online market is to curtail access using blocking mechanics. However, within the small evidence base, the effect of different types of blocking suggests different levels of effect with issues of compliance and enforcement to navigate.

With the aim, in part, to increase consumer protection from the unregulated online gambling industry, Quebec introduced a state monopoly on online gambling—Espacejeux ((Loi sur la Société des loteries du Québec [Act respecting the Société des loteries du Québec], CQLR S-13.1 [94]) Using two cross-sectional surveys of large datasets of gambling habits in 2009 and 2012, a study by Kairouz and colleagues examined the effect of this regulatory change [79]. Overall channelling activity towards regulated sites and away from unregulated sites did not reduce the prevalence of unlicensed gambling. However, Québec’s monopoly, Société des lotteries du Québec, did not increase the overall prevalence of gambling either, and the rates of gambling remained stable within the population. The rates of harmful gambling also remained stable. A later situational analysis of this rule examined the complexities of regulating online gambling [78]. It suggested that a narrow approach detracts from the range of risks to which consumers are exposed (focusing on the problem gambler or addiction only) and the inequities generated by variances in experiences of subgroups of the population and how these inequities contribute to overall intervention efficacy are not considered.

A large-scale European evaluation of the effectiveness of regulatory tools to control online gambling employed by authorities in European Economic Area (EEA) countries was undertaken in 2018 [72]. Ultimately the regulatory aims of the included EEA member states were similar in that they aimed to reduce the risk of gambling harms and protect consumers from unfair (misleading advertising) and unsafe (underage gambling) practices. Regulatory strategies consisted of a range of blocking systems, including payment and website blocking, advertising regulations, and other sanctions. The evaluation found that compliance with blocking systems was considerably lower than the initial uptake and implementation of blocking systems.

Egerer and colleagues’ [82] recent scoping review of the effectiveness of blocking regulations empirically corroborates the European Commission report of 2018 [72]. With 14 studies including empirical studies of effect, case studies and legal analyses, this global review highlighted variation between jurisdictions due to the type of blocking (payment or website blocking or a combination) and a lack of comprehensive implementation strategies. Challenges with maintaining blocklists affected implementation. Automatic blocking can lead to over-blocking, whereas manual regulators are expensive and time consuming. In the small evidence base, combined blocking was deemed most effective. Blocking is made less effective by tech-skilled users who can circumvent blocks, for example, changing IP addresses, using VPNs, and other fast-tech adaptations enabled by offshore providers. The financial gain that offshore industries can generate is incentivising fast adaptations to blocking strategies, in comparison to longer state regulatory processes.

Jurisdictions utilising landing pages reported the most effect in reducing access to unlicensed gambling by redirecting consumers to alternative sites away from unlicensed sites. Landing pages are webpages that consumers are redirected to when they are trying to reach a blocked site. They have been recommended as a tool for reducing unlicensed gambling by other academics in the sector [73], however it is important to implement them effectively by utilising several languages to communicate that the blocked website is unlicensed, offering links to licensed gambling sites, self-help materials, and regulators, and including warnings about the economic and legal risks of accessing unlicensed sites [73].

Overall, the ability to block unlicensed online gambling seems to appeal to many states and with the correct regulatory implementation and enforcement this could improve online gambling harm reduction by directing consumers back to regulated markets. An emerging regulatory tool, known as bank gambling blocks (BGBs) and delivered by the banking industry, enables a more targeted enforcement of payment blocks [68, 95, 96]. This allows consumers to block gambling payments being taken from their accounts. Most major banks have agreed to participate in the UK, although globally the tactic is less commonly used [95]. The strategy includes a package of transaction data monitoring and communication with individual customers using support messages and direct communication. In the UK, a recent report examining the effectiveness of BGBs as a harm reduction strategy found that they have been effective but cannot be offered as a complete solution as BGBs do not treat the wider causes and address the wider implications of harmful gambling. However, they offer a safety net to prevent further financial harm [68]. The ability to recognise individuals at risk of online gambling harm through transaction data enables earlier intervention to activate BGBs and also offer signposting to wider support. For those individuals utilising the service, the level of public awareness was considered inadequate, with customers often experiencing considerable harm before accessing BGBs. More effective promotion of the tool is therefore required. Challenges also exist with this intervention. Gambling operators may miscode transactions to avoid a block, and non-card transactions are not included in BGBs and can be utilised as a work around the block. In addition, customers generally do not reach out for help until they are in crisis, when serious harm may likely already have occurred. BGBs are also at risk of being underutilised, understood only as a tool for a self-identified minority of ‘problem gamblers’ [89]. Rapid expansion would, however, pose challenges for banks and other actors, in that if the program became more successful as an early intervention model, the infrastructure may be insufficient to support the volume of customers needing help. Whilst BGBs remain in their infancy as gambling harm reduction tools, regulators need to consider how they can provide additional support for those experiencing harm by developing robust minimum standards and guidelines for banks and gambling operators and improving signposting to and resourcing of treatment and recovery services.

Research on the health equity and equality impacts of laws and regulations intended to reduce online gambling harms

Very few studies address the health equity and/or equality effects of laws and regulations intended to reduce online gambling harms. We know that in the online gambling space individuals identifying as male, and young people, are disproportionately at risk of gambling harms [97–99]. In the literature this is generally discussed in terms of prevalence rates, risk factors, and behaviours. There is a general lack of evidence regarding the efficacy of legal interventions to reduce gambling harm for those subgroups of the population. There are some exceptions regarding children and young people, including in research on the impact of age restrictions [75, 76, 80, 83], and advertising restrictions [77, 83].

Age restrictions

A review of the evidence by Shi [83], observed a very small number of studies which explore youth gambling harms in relation to online gambling and regulation [76, 80]. This review captured a significantly higher number of irrelevant studies pertaining to young people’s land-based gambling behaviours and the original articles were examined instead. In Finland, the minimum age of gambling increased from 15 to 18 across 2010 and 2011 (1047/2001 Arpajaislaki [Lotteries Act]). While levels of online gambling increased for all other age groups, no increase was observed for 15–17-year-olds [76]. The primary reason posited for the lack of increase in underage online gambling was the strong identification required to register as customer for the national monopoly. However, it is possible that the age group of 15–17-year-olds could utilise offshore gambling sites as an alternative. Nordmyr, who explored the same regulatory change in the context of ‘problem gambling’ prevalence rates, could not find any statistically significant results related to younger people’s online gambling behaviours as there were zero respondents in the 15–17-year-old category [75]. For Australian young people, age restrictions reduced access for underage gamblers, however facilitators such as friends or family members over-18 could easily bypass this rule [80].

Young people are known to underestimate the risks associated with online gambling, understanding gambling in terms of fun and gaming [80]. The difference in neurodevelopment in young people, compared to adults, could explain the appeal for online gambling as a fun activity, understood to be devoid of risk [83]. However, a distinct lack of rigorous evidence—particularly a lack of participants in younger age groups [75]—needs addressing to improve our understanding of why these outcomes occur and which legal and regulatory interventions are best placed to address them.

Advertising restrictions

Many jurisdictions have laws in place to restrict gambling advertising to children and young people. Spanish online gambling regulation is bound to Article 149 of the Constitution, and additional obligations to inform minors and vulnerable others are set in Article 6.2, Act 13/2011, dated 27 May, on Gambling Regulations (LRJ) and Article 26 of Royal Decree 1613/2011, meaning government acknowledge the harmful influence of advertising on children and young people. One legislative analysis has examined the efficacy of this regulation in protecting minors [77]. This study found that children and young people are not adequately protected from gambling advertising, notwithstanding Spain’s relatively robust legal framework. Although the online industry is obligated to inform children (minors) and other vulnerable groups on the prohibition, this is not widely enforced. Through sports sponsorships, minors are exposed to bookmakers’ advertising through sports team sponsorship and advertisements on players shirts with no repercussions. These types of breach of the code could be reinforcing the message to children and young people that online gambling is a leisure activity associated with healthy habits (sport), a risk identified in other empirical research on gambling more broadly [100].

Overall, there is paucity of work on the equity effects of laws and regulations intended to address online gambling harm. We have only found empirical research which includes children and young people as a subgroup, and clearly this is not a comprehensive account of gambling harm and inequalities.

Conclusion

While there is a consensus that inadequate legal and regulatory frameworks have played a crucial role in the proliferation of online gambling harms, studies vary in their explanation for this inadequacy. Some studies subscribe to a ‘law lag’ explanation for poor controls on online gambling, whereas others identify the role of regulatory capture by pro-technology innovators, such that pro-industry, liberalising legal frameworks are understood to have co-created subsequent harms. In that light, additional research is required to understand the reasons why jurisdictions regulate online gambling in particular ways, and to reduce the influence of industry experts on regulators.

There is also an urgent need for further research on law, regulation, and online gambling harms to explore the broader harmful implications of digital technology, and the harmful innovations that may be enabled by pro-technology legal regulation.

Research should also explore how interventions designed to mitigate online gambling harms may inadvertently create and/or exacerbate IGIs. The equity effects of legal interventions were not a priority for the majority of included studies. However developing equitable regulation is crucial to improving the efficacy of laws and regulations that can protect individuals at risk of gambling harms, their loved ones, and the wider community, and that also mitigate against unintended negative consequences of legal interventions. By focusing on the intersection of gambling harms, regulation, and risk derived from online gambling specifically, researchers can offer valuable insights into how laws and policies can be better designed to protect individuals while reducing disparities across different subgroups of the population.

The policy implications of our review of evidence are threefold. Firstly, multiple included studies indicate that adequate resourcing to ensure compliance with legal interventions is a key priority. Changing a law without adapting a compliance ecosystem to effectively enforce that law will likely result in ineffective protection. Secondly, lawmakers and enforcers need to ensure strict independence from the online gambling industry, and associated digital technology industries, so that the legal framework is henceforth designed and operationalised in public rather than corporate interests. Pro-innovation legal frameworks, shaped by a range of industries, have had a key role in exacerbating online gambling harms: better regulation necessitates a reduction in industry influence on future rules. Finally, several included studies point to the importance of stricter, more robust definitional boundaries around terms that are especially crucial for effective legal control of online gambling. Some failures to address harm result from inadequate legal definitions, especially around advertising (e.g. if defined in a way that excludes much online marketing), and gaming. Once again, this could be partly addressed by better resourcing regulatory capacity to address online gambling harm, including across borders.

Electronic Supplementary Material

Below is the link to the electronic supplementary material.

Author contributions

J.S.C. and K.B. obtained study funding. M.L.F., T.P., M.F., J.S.C., K.B., and G.F. conceptualised the scoping review; M.L.F., K.B., J.S.C., G.J.M-T., P.M-M., and G.F. developed the inclusion/exclusion criteria, J.K., M.L.F., T.P., S.M., M.F., and K.B. developed the search strategy. All authors substantially contributed to and revised the manuscript and/or provided critical feedback on the manuscript. All authors read and approved the final manuscript.

Funding

This study is funded by the NIHR PHR programme (NIHR156218). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

The systematic review of evidence does not involve human participants. No ethical approval is required for that dimension of the research.

Consent for publication

Not applicable.

Competing interests

MLF, SM, AR, JSC, GJM-T, CB-J, & JK declare that they have never sought or received gambling industry funding to conduct research, to testify, or to provide evidence of any kind. They have never sought or received payment or funding from private companies that profit from problem gambling diagnosis or treatment or from offering ‘responsible gambling’ services (including ‘safer gambling’ software). They have never sought or received payment or funding to advise government agencies seeking to expand gambling (see Additional file 1).