The last decade has seen a marked increase in gambling availability and participation. This increase is in part due to a rapid proliferation in digital platforms of gambling delivery, including online betting and smartphone betting applications. In turn, this rise in gambling availability and participation has led to an increase in the prevalence of gambling-related issues. This is particularly concerning, as relatively few problem gamblers ever engage in treatment, despite experiencing substantial psychological and social impairment as a result of their gambling. Difficulties with engagement are likely to stem from the many barriers problem gamblers face when seeking treatment, including financial issues, stigma, embarrassment and shame. Successful utilisation of digital technologies may help overcome barriers often faced by more traditional face-to-face mental health assessments and interventions, with these novel forms of digital delivery being potentially better suited to fostering user engagement, motivation and retention in mental health assessments and interventions. To date, virtual reality technologies present as one the most efficacious forms of digital mental health assessments and interventions, providing a range of interactive systems, environments and mechanisms by which mental health assessment and intervention can be enacted. Review of the literature and meta-analysis, as reported in Chapter 3, supported the efficacy of virtual reality-based interventions, though issues regarding methodological rigour remain. Yet despite the promise of virtual reality-based assessments and interventions, their development and implementation has been sluggish. For this reason, there appears to be a need to explore the utility of alternative digital delivery platforms. Video games provide a more readily-accessible, cost-effective digital delivery platform for mental health assessment and intervention. Mental health video games aim to make the processes of change and learning more meaningful and engaging. As is reported in Chapter 4, review of the literature revealed that mental health video game assessments and interventions have successfully been investigated in the assessment and treatment of a number of populations and presentations. Moreover, it was observed that mental health video games may pose a particularly useful platform for engaging hard-to-reach populations such as problem gamblers, engaging users emotionally, capturing their attention and promoting continuing engagement. However, it was concluded that the lack of empirically supported theory, methodological rigour and psychometric validation in the literature makes it difficult to draw overall conclusions regarding the efficacy and utility of mental health video games. It was determined that there remains a need in the literature for robust examples of the development and implementation of empirically driven, well-validated mental health video games. The overall aim of this thesis was to explore the role digital technologies can play in the development and delivery of mental health assessment and intervention, with particular focus placed upon the area of problem gambling. To this end, a novel mental health video game assessment of problem gambling was developed (SLOTZ). Game play was developed in accordance with game design and gambling-related neuropsychological theory. Initial conceptualization, development, piloting and the first iteration of revision and refinement of SLOTZ game play is described over the course of Chapter 5 and Chapter 6. Levels of immersion and engagement were found to be high, with participants observed to find SLOTZ game engaging and enjoyable. Two SLOTZ sub-tests were observed to significantly correlate with established measures of gambling severity and to demonstrate an ability to significantly predict gambling severity in participants. Implications, limitations and directions for future research are discussed in Chapter 7 and Chapter 8. Overall, findings from this thesis provide evidence that problem gambling can be identified and predicted via video game play. SLOTZ presents as an economical, engaging, enjoyable, and psychometrically validated means of problem gambling assessment that is likely to be wide-in-reach and less psychological, socially and financially aversive to populations who are historically difficulty to engage. Moreover, this thesis provides a sound example of the process of empirically testing digital mental health video assessments and interventions via a multi-step iterative process of pilot testing and refinement, demonstrating the utility of video games in mental health assessment and interventions.