Table 1.

Study characteristics of included studies (n = 23).

	Study design			Population Age (years), Sample Size Intervention Name	Primary Aim	Digital intervention platform						Aim classification			Field of inquiry
First Author (YYYY) Location Country	Qualitative	Randomised Controlled Trial	Quasi-experimental			WebSite	App	Short Animated Films	SMS	Social Media	Other	Descriptive	Evaluative	Investigative	General Wellbeing	Physical Activity	Chronic Disease	Risk Mitigation	Mental Health
Alonso (2021) United States	⊠			16–35, 462 weCare	To use social media to increase HIV care engagement among young gay, bisexual and other men who have sex with men, and transgender women who are living with HIV, particularly those who identify as Latino					⊠		⊠					⊠
Bidargaddi (2017) Australia		⊠		16–25, 387 The Toolbox	To assess the efficacy of a web-based self-guided app recommendation service in improving the well-being of young Australians	⊠								⊠					⊠
Cheng (2018) Australia	⊠			16–35, 40 MindMax	To identify the best way to structure and present MindMax, an app that aims to deliver psychoeducation modules and create a web-based community centring on wellbeing, AFL and video games for men aged 16 to 35 years		⊠						⊠						⊠
Coughlan (2021) Europe (Dublin, Ireland)	⊠			18–21, 17 SpunOut	To translate qualitative research findings into a series of online published mental health animations targeting young people			⊠				⊠							⊠
Coyne (2016) Europe (Dublin, Ireland)	⊠			15–25, 21 www.steppingUP.ie	To co-develop an e-health information intervention to support young people with long-term illnesses transitioning to adult healthcare	⊠							⊠				⊠
Davis (2017) Australia	⊠			15–24, 20 Kiss myAsthma	To develop an evidence-based asthma app tailored to young people's needs, created using a participatory design approach to optimise user engagement		⊠						⊠				⊠
Gan (2023) Australia	⊠			18–25, 16 LifeBuoy (Engagement Strategy)	To detail the processes and activities involved in developing an adjunctive strategy for promoting engagement with LifeBuoy					⊠		⊠							⊠
Graham (2013) United States	⊠	⊠		18–35, 1689 e-Moms Roc	To describe the development and use of e-Moms of Rochester, and electronic intervention to address gestational weight gain in a socioeconomically diverse sample of pregnant women	⊠							⊠		⊠
Greer (2019) United States		⊠		18–29, 45 Vivibot	To examine the feasibility of delivery of positive psychology skills via the Vivibot chatbot and its effects on key psychosocial well-being outcomes in young adults being treated for cancer					⊠				⊠			⊠
Griffiths (2015) United Kingdom				16–30, 12 Realshare	To design and evaluate the acceptability of the Realshare online community	⊠							⊠				⊠
Hallett (2009) Australia	⊠			17–24, 2435 THRIVE	To describe the process of developing and implementing an electronic screening and brief intervention in a large university population	⊠					⊠		⊠					⊠
Heckman (2015) United States		⊠		18–25, IIa (n = 25); FGb (n = 4–8); CIc (n = 20); Ad (n = 5–15); Ue (n = 12); PTf (n = 46) UV4.me	To describe the development of an online skin cancer risk reduction intervention for young adults	⊠							⊠					⊠
Hightow-Weidman (2011) United States	⊠			18–30, FGb (n = 5–8), UTg (n = 4–7) HealthM powerment.org	To describe results from formative work in developing a theory-based online HIV/STI prevention intervention for young black men who have sex with men	⊠							⊠					⊠
Ito-Jaegar (2022) United Kingdom	⊠			17–21, 39 What's Up With Everyone?	To explore young people's perceptions of co-created animated films for the What's Up With Everyone campaign to promote mental health literacy among young people			⊠					⊠						⊠
Lederman (2014) Australia	⊠			15–25, FGb (n = 6), Ue (n = 6), PEj (n = 23) MOST	To discuss methods and results in the light of existing design frameworks for youth mental health, and report experiences which will be useful for other researchers in the field	⊠							⊠						⊠
Meyer (2007) United Kingdom	⊠			Unspecified (university), 10 Student depression.org	To construct a comprehensive self-help website for university students providing a multi-layered account of depression to website users offering empowering perspectives and strategies	⊠						⊠							⊠
Ospina-Pinillos (2018) Australia	⊠			16–25, 34 Mental Health e-Clinic	To use participatory design as research methodologies with end users and the research team to develop the Mental Health e-Clinic	⊠							⊠						⊠
Ospina-Pinillos (2019) Australia	⊠			16–30, 17 Mental Health e-Clinic	To use participatory design methodologies to (a) co-design and culturally adapt the MHeC, (b) inform MHeC alpha prototyping, (c) test usability, (d) translate, culturally adapt and face-validate the MHeC self-report assessment and (e) collect information to inform beta prototype	⊠							⊠						⊠
Pachankis (2013) United States	⊠			18–30, 13 MiCHAT	To describe the development of the online intervention and highlight the results of interviews and focus groups with the original intervention participants regarding effective adaptation and online delivery recommendations					⊠		⊠						⊠
Patchen (2020) United States	⊠			15–21, 86 SAAFE	To identify the optimal modality for a game-based sexual health intervention; develop the educational, entertainment and technological aspects of the serious game, and demonstrate its usability and acceptance						⊠		⊠					⊠
Rice (2018) Australia				15–24, 42 Rebound	To conduct a single-group pilot study to evaluate the acceptability, feasibility, usability and safety of a novel, moderated online social therapy intervention for depression relapse prevention in young people	⊠								⊠					⊠
Simons (2018) Belgium	⊠			18–26, Ue (n = 11), Ad (n = 16) Active Coach	To describe the development, usability, acceptability and feasibility of a new theory- and evidence-based smartphone app to promote an active lifestyle in less educated young adults		⊠						⊠			⊠
Wright (2016) Australia				18–25, 40 MIDY	To investigate the feasibility and acceptability of a mobile-phone delivered Ecological Momentary Assessment and brief intervention for young people during drinking events						⊠		⊠					⊠