Keywords
Gambling, risk factors, young adults, systematic review
Gambling is increasingly getting recognised as a public health problem, with young adults (18–25) being identified as a particularly vulnerable group due to their ongoing neurodevelopment and increased exposure to spreading gambling environments. Individuals who adopt problematic gambling behaviours can either classify as problem gamblers or can in more severe cases meet the criteria for a clinical diagnosis for Gambling Disorder (GD). Different characteristics and traits, known as risk factors, can influence the development of these conditions. This review aims to evaluate the quantitative studies investigating risk factors contributing to problematic gambling behaviours in the young adult populations.
A systematic review guided by the Joanna Briggs Institute (JBI) methodology will be conducted. This review will consider quantitative and mixed-methods, where quantitative data can be extracted, evidence published from 1990 onwards on risk factors which are associated with gambling in the young adult population. Four databases will be searched as well as grey literature. Methodological quality will be assessed using the JBI critical appraisal tools based on the study designs of each study. Data extraction will be conducted using the JBI standardised extraction tools. The risk of bias will be assessed using the Quality in Prognostic Studies (QUIPS) tool to evaluate the risk-factor-outcome relationship.
Gambling Disorder and Problem Gambling are a growing public health concern. The results of this review are anticipated to benefit researchers, clinicians and policymakers by providing a better understanding on key predictors of gambling-related harm in this population which would then aid in informing early intervention and prevention strategies.
Protocol registration number PROSPERO 2026 CRD420261288057.
Gambling, risk factors, young adults, systematic review
We would like to sincerely thank Prof Browne and Dr Bolat for their valuable feedback on the protocol for our systematic review. Their expertise and thorough review have greatly contributed to the improvement of this protocol and we are appreciative of the time and effort they afforded to this process. In the Methods section, we have refined the inclusion criteria to include studies that examine predictors/exposures related to future and concurrent PG/GD. We have also defined primary and secondary outcomes more clearly. The age band rule of 18-25 years and its application for study selection have been clarified. The search strategy for grey literature has also been expanded. In the Data synthesis section, we provided further clarification on including both longitudinal and cross-sectional studies and how results from different study designs will be handled. We have also elaborated on our data analysis approach, including the rationale for quantitative synthesis, narrative synthesis and assessment of evidence certainty using the GRADE tool. We have incorporated all the useful suggestions within the reviewer report including improvement of language and terminology throughout the protocol.
See the authors' detailed response to the review by Matthew Browne
See the authors' detailed response to the review by Elvira Bolat
For many people, gambling is a form of a leisure activity. However, persistent participation can lead to Problem Gambling (PG) and, in more severe cases, a clinically recognised behavioural addiction known as Gambling Disorder (GD) (Krotter et al., 2025). Gambling has increasingly become recognised as a public health issue (Tran et al., 2024). The recognition was first evident with the definition of excessive gambling in the International Classification of Diseases (ICD), followed by the development of the diagnostic criteria included in the Diagnostic and Statistical Manual of Mental Disorders, third edition (DSM-III) (Tran et al., 2024). PG refers to gambling behaviour that results in significant harm to the individual and their relationships (Scholes-Balog et al., 2014). Individuals with PG may display symptoms associated with GD, but do not necessarily meet the full criteria for a clinical diagnosis (Afifi et al., 2016). The Problwm Gambling Severity Index (PGSI) is the most widely used tool to measure PG and has been used in numerous epidemiological studies worldwide (Gavriel-Fried et al., 2024). GD is a psychiatric condition which is characterised by a maladaptive pattern of gambling behaviour that persists despite its negative impacts on major areas of life functioning (Ferrara et al., 2018). It is frequently associated with impulsive behaviour which can lead to harmful long-term harm (Leppink et al., 2016).
Despite substantial variations in prevalence rates, the literature consistently demonstrates an elevated risk of PG among young adults relative to other populations (Duggan & Mohan, 2023). In Ireland, a report by Mongan et al. (2022) revealed that in 2021, almost half (49%) of adults aged 15 and over engaged in some form of a gambling activity. Young adults aged 18–25 years are considered a particularly at-risk population, as this developmental stage is often described as “vulnerable” (Chambers & Potenza, 2003). This is a crucial stage in cognitive development which is associated with identity explorations, personal development and changes in different areas of life, which increases susceptibility to behavioural addictions, including gambling (Chambers & Potenza, 2003; Gavriel-Fried et al., 2024; Lambuth et al., 2026).
Furthermore, the increasing availability of gambling services which have spread onto online platforms, have made gambling more accessible and convenient for young populations (Bickl et al., 2024; Hollén et al., 2020). This raises the potential of development of Addictive forms of gambling and negative outcomes including strain on finances, damage to mental and physical health, relationships, employment and education (Duggan & Mohan, 2023; Tran et al., 2024). Therefore, it is important to note the early appearance of risk behaviours as they can, if left untreated, result in severe disorders in later adulthood (Bozzato et al., 2020). This has been supported by the research that found that individuals who were classified as problem gamblers in early adulthood are more likely to remain problem gamblers with a more serious diagnosis in later adulthood (Emond et al., 2022; Kerr et al., 2021).
In order to inform policies about the issue of young adults adopting problematic gambling behaviours, it is important to understand which factors contribute to their development (Duggan & Mohan, 2023). Risk factors are conditions and traits which, if present, make an individual at a higher risk of developing a condition (Mrazek & Haggerty, 1994). As of now, a wide range of risk factors associated with problematic gambling behaviours have been identified in multiple primary studies and systematic reviews (Bickl et al., 2024). These risk factors can change throughout different life stages, and they can arise from the individual, their family, peers or environment. They can also be biological and psychosocial (Mrazek & Haggerty, 1994). Therefore, it is essential to have a thorough understanding of them and how they impact the development of PG and GD in different age groups (Calado et al., 2017).
A preliminary search identified two key systematic reviews on the topic of interest. Moreira et al. (2023) conducted a systematic review on risk factors associated with GD in the general population. Risk factors were categorised at a “personal” and “familiar” level. At the personal level, factors such as being young, single male or being married for less than five years, living alone, having poor education and financially struggling were all identified as factors which contributed to increased gambling behaviour (Moreira et al., 2023). At the familiar level, it has been identified that individuals that qualify as gamblers experience greater difficulties with family and social relationships than non-gamblers (Moreira et al., 2023). In addition, individuals who grew up with a single parent or parents with addiction problems were more likely to experience gambling problems (Moreira et al., 2023). While this systematic review covers a range of risk factors, the overall focus is on how they impact the general population which makes it difficult to extract the evidence concerning young adults specifically.
A more focused review was conducted by Dowling et al. (2017) who published a systematic review and meta-analysis of longitudinal studies on early risk and protective factors of gambling that emerge in childhood, adolescence or young adulthood. They hadidentified thirteen individual risk factors, one relationship risk factors and one community risk factor which all influence the development of GD, as well as a range of protective factors (Dowling et al., 2017). This systematic review presented extensive evidence on the various risk factors, however, its focus on longitudinal studies excludes the evidence from the other relevant literature. It also remains challenging to isolate the specific factors associated specifically with young adults at the point of transition into high-risk gambling. Updating the literature beyond 2017 is also necessary to incorporate new populations, methodologies and contemporary risk factors.
Therefore, the justification for conducting systematic review on this subject is to identify and synthesise a more comprehensive understanding of the risk factors associated with gambling in young adults by integrating the existing evidence from various studies. The primary focus on young adults aged 18–25 years will broaden the spectrum from general or adolescent samples and the factors associated with the PG and GD.
A systematic review is proposed. The following questions aligned to the review question are:
• What are the risk factors associated with PG and GD in young adults aged 18–25 years?
• What factors are associated with or predict PG/GD among young adults aged 18–25 years?
The results of this review will be of value to researchers, healthcare professionals and policy makers as it may provide a better understanding of factors associated with the development of gambling-related problems in young adults.
This protocol has been designed using a framework provided by The Joanna Briggs Institute (JBI) and will adhere to the PRISMA for systematic review protocols (PRISMA-P). The methodology has adapted the PEO framework (Population, Exposure, Outcome) as suggested by JBI (Moola et al., 2017). The PEO framework assisted in the identification of defining characteristics for the inclusion criteria for the systematic review.
Population: This review will consider studies that include young adults. For this review, a young adult is defined as an individual aged 18–25 years. Two different populations of young adults will be considered for inclusion:
1. Young adults who meet the criteria for PG based on a validated screening instrument (e.g., Problematic Gambling Severity Index Scale) or whose gambling severity is evaluated on a scale
AND/OR
2. Young adults who have a formal clinical diagnosis of GD diagnosed with a universally used clinical diagnostic tool (e.g., DSM-5 or ICD-10/11).
AND/OR
3. Young adults who are studied in relation to risk factors, predictors, or exposures associated with current or future development of PG/GD, including both cross-sectional and longitudinal study designs.
Studies primarily focused on the populations aged <18 and > 25 years will be excluded. Studies reporting effectiveness of treatments and interventions for individuals diagnosed with GD where risk factors are not reported will be excluded.
Exposure: According to the JBI definition, a risk factor refers to an individual characteristic or exposure that is associated with an increased likelihood of an outcome occurring (Moola et al., 2017). Studies reporting on risk factors such as, but not limited to, psychological, social, individual, demographic, environmental and socio-economic, will be considered. Studies not defining and categorising risk factors and their association with the development of PG or GD will be excluded.
Outcome:
Primary outcome 1: Risk factors for developing GD in young adults aged 18–25 years diagnosed using validated tools.
Primary outcome 2: Risk factors for developing PG in young adults aged 18–25 years identified using screening tools.
Secondary outcome: To investigate the incidence of gambling-related behaviours, including gambling frequency and gambling participation, in the young adult (18–25) population.
Studies reporting non-gambling outcomes, such as substance use, will be excluded.
This systematic review will consider primary quantitative studies and mixed-methods studies. However, primary mixed-methods studies will only be considered for inclusion if it is possible to extract quantitative data components concerning the young adult population aged 18–25 years. Studies including a sample of wider age ranges will be included in the instances where the data on young adults between ages 18 to 25 is extractable. In instances where primary mixed-methods studies are presented in an integrated format and extraction cannot be undertaken, the studies will be excluded. Studies that report only the mean age, without clear indication of the age range of the sample, and where the 18–25 age range data is not extractable will be excluded. Editorials, comments, literature reviews, conference abstracts, guidelines, recommendations, consensus papers and qualitative studies will be excluded. Studies not directly related to the review question, but that present valuable evidence on the relationship between risk factors and gambling will be included if they meet other inclusion criteria (Moola et al., 2017).
Included studies will comprise of peer-reviewed, full texts published from 1990 to be consistent with the development of the first validated tool for the assessment of PG, the South Oaks Gambling Screen (Dowling et al., 2017; Lesieur & Blume, 1987). Grey literature will also be considered by searching the websites of relevant organisations, such as the World Health Organization (WHO) and the Health Service Executive (HSE) for the reports and unpublished studies, and institutional repositories for relevant theses. The same search limits and inclusion criteria will be applied while searching the grey literature. The reference lists of included studies will be manually searched for additional relevant papers. There will be no limitation to the language in which the study has been originally published, but a version published in English will be sought.
A systematic search strategy will be developed with a professional subject librarian. The search terms and concepts will be identified by examining MeSH subject headings which will also help us to refine our search concepts. The databases which will be systematically searched are Scopus (Elsevier), Web of Science, PubMed and APA PsycInfo. In addition, the reference lists of all included studies will be manually searched for additional studies which may be included. Boolean operators and controlled vocabulary terms will be used as required for each database search. Grey literature, including government reports and Google Scholar, will be searched based on the key terms used for the database search.
Following the search, all identified citations from each database searched will be imported into Zotero Citation Management System version 7/2025 where search results will be manually deduplicated. These will then be imported into Covidence Software for screening. Title and abstract screen will be conducted in Covidence independently by two reviewers where they will be assessed against the review’s eligibility criteria. All potentially relevant titles identified by either or both reviewers will be moved forward for a full-text review. The full texts of the selected studies will be assessed in detail by two independent reviewers using the eligibility criteria. Each full text study which is excluded will be documented and reported in the Appendix section of the systematic review (Moola et al., 2017). Any disagreements that arise between the reviewers will be settled through discussion or with the assistance of the third independent reviewer in the instances where the disagreements cannot be resolved. The complete results of the search will be reported in the final review and presented in a Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) flow diagram (Moola et al., 2017).
The studies identified for inclusion will be appraised and evaluated for the methodological quality using the JBI critical appraisal tools which should be applied based on each study’s methodology (Moola et al., 2017). The assessment of methodological quality will be conducted independently by two reviewers. If the two reviewers disagree on the final critical appraisal, a third independent reviewer will be consulted. Data extraction and data synthesis will be conducted on all studies included in the final review despite the result of their methodological quality (Moola et al., 2017).
Two independent reviewers will extract all quantitative data using the JBI standardised data extraction tools which allow the extraction of the same types of data across the included studies (Moola et al., 2017). Any disagreements will be resolved through discussion until agreement is reached. In instances where agreement cannot be reached, a third independent reviewer will be consulted (Moola et al., 2017).
The following information will extracted: study characteristics including authors’ names and year the study was published in, study design, setting of the study, recruitment design, population’s characteristics including sample size and age range, follow-up or the duration of the study, items identified as risk factors, participants’ exposure vs non-exposure to the risk factors, primary outcome measures and risk of bias (Moola et al., 2017). Study authors will be contacted for any missing information or clarifications essential for data synthesis. Authors will be contacted by email a maximum of two times with the emails sent three weeks apart.
The risk of bias will be assessed using the Quality in Prognostic Studies (QUIPS) tool. While the JBI highly recommends the use of JBI tools for the review, the exemptions can be made where the appropriate justification for the use of different tools is given (Moola et al., 2017). The JBI tool is designed to assess the quality of a wide range of study designs and it, therefore, includes multiple separate tools which are adapted depending on the study design (Moola et al., 2017). In comparison, QUIPS is a single tool that is more suitable as it is specifically created for assessment of risk of bias in the prognostic factor studies where the bias is evaluated in the risk factor-outcome relationship (Hayden et al., 2013).
Given the inclusion of multiple study designs, findings will be interpreted based on the strength of inference permitted by each design. Longitudinal studies will be used to identify predictive risk factors for PG/GD, while cross-sectional studies will be interpreted as identifying associations with PG/GD rather than causal relationships. Depending on the availability and comparability of data, the evidence will be synthesised using a combination of quantitative and narrative approaches. Meta-analysis will be conducted where studies are sufficiently homogeneous in terms of study design, populations, exposures and outcomes. Where this is not feasible, findings will be synthesised narratively.
Meta-analysis will be conducted where two or more studies report comparable outcomes. Quantitative data will be pooled based on risk-factor-outcome associations through the use of Odds Ratios (ORs) and Relative Risks (RRs). A random-effects model will be employed as the primary approach to meta-analysis. A fixed-effect model will not be used as it assumes a common underlying effect size in all studies, which is unlikely in this review. Clinicaland methodological homogeneity will be assessed across study populations, definitions of risk factors and outcome measures (Moola et al., 2017). Considering that the inclusion criteria includes participants aged 18–25 years who either have a formal clinical diagnosis of GD or meet the criteria for PG, subgroup analysis will be conducted if appropriate. This analysis will allow us to examine whether risk-factor-outcome associations differ in severity or consistency across GD compared to PG groups which will, therefore, strengthen the applicability of the findings. Subgroup analyses will only be possible if at least two methodologically comparable studies are identified within each subgroup.
Where quantitative synthesis is feasible, findings will also be stratified to enhance interpretability and account for heterogeneity. Primary stratification will be by study design, distinguishing longitudinal studies (used to identify predictive risk factors) from cross-sectional and case-control studies (used to identify associative factors). Findings will also be stratified by outcome type where appropriate.
Due to anticipated heterogeneity in research designs and variabilities in study and reporting methods, a full meta-analysis may not be feasible. Therefore, a comprehensive narrative synthesis will be primarily utilised. The characteristics of the study will be narratively summarised in the tables of the report according to risk factors to investigate the consistency of correlations. Extracted data will be presented in the tables as frequencies and percentages, means and standard deviations, or medians and interquartile ranges, as appropriate. Risk factors will be categorised based on their concept (i.e. demographics, social, psychological) to facilitate narrative synthesis (Moola et al., 2017). Where appropriate, findings will be grouped by outcome or risk factor. The strength of evidence within each group will be considered based on study quality and findings.
The quality of evidence will be assessed by two independent reviewers using the Grading Recommendations Assessment, Development and Evaluation (GRADE) approach for prognostic factor research (Huguet et al., 2013).
This Systematic review protocol has been developed and registered on PROSPERO (CRD420261288057). The review is currently undergoing the systematic search which will be followed by screening, data extraction and data synthesis as outlined above.
GD and PG among the young adult population is a growing public health concern (Gavriel-Fried et al., 2024). However, the associated risk factors associated with it remain insufficiently synthesised. Young adults are particularly vulnerable due to their ongoing neurodevelopment, heightened impulsivity and exposure to expanding gambling environments (Lambuth et al., 2026). Although existing evidence has identified various potential risk factors, the evidence is dispersed across different study designs, populations and methodologies, limiting the generalisability of evidence for prevention and early intervention.
This systematic review, guided by the JBI methodology, aims to address these gaps by providing a comprehensive and methodologically inclusive review of quantitative evidence on risk factors associated with GD and PG among young adults aged 18–25 years. The review will incorporate different study designs while risk factors will be categorised across different areas. Subgroup analysis, if conducted, will further enhance the understanding as it will explore differences between clinically diagnosed gamblers and problem gamblers. As such, the review is expected to provide an up-to-date overview of available evidence focused specifically on young adults.
It is expected that the findings of this systematic review will benefit researchers, clinicians and policymakers by providing a clarification on key risk factors of PG and GD and informing prevention and intervention strategies (Moola et al., 2017).
The completed review will be submitted for a publication in a peer-reviewed journal. It will be openly accessible and will be shared at relevant academic and professional conferences.
Reporting guidelines
Zenodo: “PRISMA-P checklist for a systematic review”. https://doi.org/10.5281/zenodo.18327348 (Banozic et al., 2026b).
Search strategy
Zenodo: “Example of a search strategy for “Risk Factors Associated with Gambling in Young Adults: A Systematic Review Protocol”. https://doi.org/10.5281/zenodo.18374648 (Banozic et al., 2026a).
Data are available under the terms of the Creative Commons Attribution 4.0 International License (CC-By 4.0).
The authors would like to acknowledge Emma Stapleton, Subject Librarian for the School of Nursing, Psychotherapy and Community Health, Dublin City University for her assistance in the development of the search strategy.
Competing Interests: No competing interests were disclosed.
Reviewer Expertise: Gambling studies, statistical modelling.
Is the rationale for, and objectives of, the study clearly described?
Partly
Is the study design appropriate for the research question?
Partly
Are sufficient details of the methods provided to allow replication by others?
Yes
Are the datasets clearly presented in a useable and accessible format?
Not applicable
Competing Interests: No competing interests were disclosed.
Reviewer Expertise: Gambling and marketing
Is the rationale for, and objectives of, the study clearly described?
Partly
Is the study design appropriate for the research question?
Partly
Are sufficient details of the methods provided to allow replication by others?
Yes
Are the datasets clearly presented in a useable and accessible format?
Not applicable
Competing Interests: No competing interests were disclosed.
Reviewer Expertise: Gambling studies, statistical modelling.
Alongside their report, reviewers assign a status to the article:
| Invited Reviewers | ||
|---|---|---|
| 1 | 2 | |
|
Version 2 (revision) 16 Apr 26 |
read | |
|
Version 1 20 Feb 26 |
read | read |
Provide sufficient details of any financial or non-financial competing interests to enable users to assess whether your comments might lead a reasonable person to question your impartiality. Consider the following examples, but note that this is not an exhaustive list:
Sign up for content alerts and receive a weekly or monthly email with all newly published articles
Register with HRB Open Research
Already registered? Sign in
Submission to HRB Open Research is open to all HRB grantholders or people working on a HRB-funded/co-funded grant on or since 1 January 2017. Sign up for information about developments, publishing and publications from HRB Open Research.
We'll keep you updated on any major new updates to HRB Open Research
The email address should be the one you originally registered with F1000.
You registered with F1000 via Google, so we cannot reset your password.
To sign in, please click here.
If you still need help with your Google account password, please click here.
You registered with F1000 via Facebook, so we cannot reset your password.
To sign in, please click here.
If you still need help with your Facebook account password, please click here.
If your email address is registered with us, we will email you instructions to reset your password.
If you think you should have received this email but it has not arrived, please check your spam filters and/or contact for further assistance.
Comments on this article Comments (0)