Table 1.
Study characteristics.
| Author | Primary studies | Intervention, digital platform | Outcome | Comparison interventions | Total sample | Participants age (range and mean, if available) | Geographical coverage |
| Barnes et al (2018) [28] | Systematic review of 2 RCTsa and 3 NRSsb on 3 games | Video games | Anxiety | Nonactive (alternative nontherapeutic video game) | 410 | Up to 19 years | China, Hong Kong, the Netherlands, and the United Kingdom |
| Bry et al (2018) [29] | Systematic review and content analysis of 121 apps | Mobile apps | Anxiety | No control group | Not reported | Not defined (children and adolescents) | Not defined |
| Grist et al (2017) [30] | Systematic review of 23 NRTsc and 1 RCT on 15 apps | Mobile apps | Mental health, well-being, anxiety, depression, suicide, obsessive-compulsive disorder, and eating disorders | Active (nondigital intervention; nb. Only one RCT included in the review) | 1054 | Up to 18 years | Australia, Canada, Denmark, Ireland, the Netherlands, and the United States |
| Hollis et al (2017) [24] | Systematic review of 30 RCTs; meta-review of 21 articles on 147 interventions | Internet-based interventions, mobile apps, and eHealth | Anxiety, depression, attention deficit hyperactivity disorder, autism spectrum disorder, psychosis, eating disorders, and posttraumatic stress disorder | Mixed nonactive (waitlist, no intervention) and active (attention control group, limited intervention) | 5333 | Up to 25 years | Australia, China, the Netherlands, New Zealand, Norway, Israel, Sweden, Switzerland, the United Kingdom, and the United States |
| Davies et al (2014) [31] | Systematic review of 17 RCTs and meta-analysis of 14 RCTs | Computer-delivered or web-based interventions | Anxiety, depression, psychological distress, and stress | Mixed nonactive (no treatment, waitlist) and active (alternative materials) | 1480 | 17-51 years; mean 22.6 years | Australia, Canada, Norway, Spain, the United Kingdom, and the United States |
| Farrer et al (2013) [32] | Systematic review of 26 RCTs and 1 randomized trial | Internet-based, audio, virtual reality, and computer programs | Anxiety and depression | Mixed nonactive (no intervention, waitlist) and active (attention control group) | Not reported | 18-25 years | Australia, Belgium, China, Italy, the Netherlands, Spain, the United Kingdom, and the United States |
| Valimaki et al (2017) [33] | Systematic review of 22 RCTs and meta-analysis of 15 RCTs | Internet-based interventions | Depression, anxiety, and stress | Mixed nonactive and active (not specified) | 4979 | 10-24 years | Australia, Canada, China, the Netherlands, New Zealand, Norway, the United Kingdom, and the United States |
| Harrer et al (2019) [34] | Systematic review of 48 randomized trials | Internet-based psychological interventions | Anxiety, depression, stress, sleep problems, eating disorders, and well‐being | Mixed nonactive (waitlist, placebo) and active (diaries, recommendations for behavior change) | 10,583 | Up to 29 years; mean 22 years | Australia, Canada, Finland, Germany, Ireland, Norway, Romania, Spain, Sweden, the United Kingdom, and the United States |
| Garrido et al (2019) [35] | Systematic review of 27 RCTs and 13 NRTs on 32 interventions and meta-analysis of 15 RCTs | Computer, web-based, and smartphone-delivered intervention | Anxiety and depression | Mixed nonactive (waitlist) and active (alternative therapeutic intervention) | 16,874 | 12-25 years | Australia, Canada, Chile, China, Hong Kong, Ireland, Japan, New Zealand, Northern Europe, the United Kingdom, and the United States |
| Pretorius et al (2019) [36] | Systematic review of 27 qualitative, feasibility, and comparative studies and 1 RCT | Web-based help-seeking interventions | Psychological distress | No control group | Not reported | 12-25 years | Australia, Canada, Ireland, the Netherlands, the United Kingdom, and the United States |
| Ridout et al (2018) [37] | Systematic review of 9 descriptive studies on 5 interventions | Social networking sites | Depression, psychosis, health literacy, social support, and general well-being | No control group | Not reported | Up to 25 years | Australia, China, Hong Kong, and the United States |
| Podina et al (2016) [38] | Meta-analysis of 8 RCTs | cCBTd | Anxiety | Mixed nonactive (waitlist) and active (standard CBTe) | 404 | 7-18 years | Australia, Canada, Spain, and the United States |
| Ebert et al (2015) [39] | Meta-analysis of 13 RCTs | cCBT | Anxiety and depression | Nonactive (no treatment, placebo) | 796 | Up to 25 years | Australia, the Netherlands, New Zealand, Sweden, the United Kingdom, and the United States |
| Pennant et al (2015) [40] | Systematic review and meta-analysis of 27 RCTs | cCBT | Anxiety and depression | Mixed nonactive (waitlist, placebo, no intervention) and active (standard CBT) | 3389 | 5-25 years | Australia, China, the Netherlands, New Zealand, Israel, Sweden, the United Kingdom, and the United States |
| Ye et al (2014) [41] | Meta-analysis of 7 RCTs | cCBT and SMS | Anxiety and depression | Mixed nonactive (waitlist) and active (standard CBT, alternative intervention) | 569 | 7- 25 years | Australia and the United States |
| Grist et al (2019) [42] | Meta-analysis of 34 RCTs on 29 interventions | cCBT, computer-delivered attention, or cognitive bias modification programs | Anxiety and depression | Mixed nonactive (waitlist, placebo) and active (face-to-face or alternative therapeutic interventions) | 3113 | Up to 18 years | Australia, Canada, China, Ireland, Israel, the Netherlands, New Zealand, Sweden, Thailand, the United Kingdom, and the United States |
| Vigerland et al (2016) [43] | Meta-analysis of 24 RCTs | cCBT | Multiple psychiatric and psychosomatic conditions | Mixed nonactive (waitlist) and active (standard CBT, alternative intervention) | 1882 | Up to 18 years | Australia, Canada, Germany, the Netherlands, Sweden, and the United States |
| Clarke et al (2015) [44] | Systematic review of 14 RCTs and 14 NRSs on 21 interventions | Mixed web-based interventions and more than half (8/15) cCBT | Mental health promotion and prevention | Mixed nonactive (waitlist, placebo, no intervention) and active (limited intervention) | 10,779 | 12-25 years | Australia, Canada, China, Germany, Ireland, Israel, the Netherlands, Norway, and the United States |
aRCT: randomized controlled trial.
bNRS: nonrandomized study.
cNRT: nonrandomized trial.
dcCBT: computerized cognitive behavioral therapy.
eCBT: cognitive behavioral therapy.