Table 1.
Characteristics of the included studies.
| Author(s), year, country (References) | Study type | Theoretical model | Duration of intervention | Sample mental health characteristics | Target population | Baseline sample size | Primary mental health outcome | Engagement metric(s) |
|---|---|---|---|---|---|---|---|---|
| Unguided interventions (17 studies) | ||||||||
| Andersson et al., 2005, Sweden (33) | RCT | Internet-administered self-help (CBT) | 5 modules / 8 weeks | Mild to moderate symptoms of depression; based on self-report. | Adults Mage = 36.4 (11.5) 78% female |
57 | Depression | Modules completed (+) |
| Berger et al., 2011, Switzerland (34) | RCT | Internet-based self-help (CBT) | 5 lessons / 10 weeks | Fulfill diagnostic criteria for social anxiety disorder. | Adults Mage = 37.2 (11.2) 53.1% female |
81 | Anxiety (social phobia) | Lessons completed (+) Time spent (+) No. of clicks (+) No. of diary entries (+) |
| Berger et al., 2017, Switzerland (35) | RCT | Velibra (CBT) | 6 modules / 9 weeks | Fulfill diagnostic criteria for anxiety-related disorders. | Adults Mage = 42.0 (12.1) 70.5% female |
70 | Psychological distress | Modules completed (ns) Time spent (ns) |
| Bolier et al., 2013, Netherlands (36) | RCT | Psyfit (Positive psychology) | 6 modules / 8 weeks | Mild to moderate symptoms of depression; based on self-report. | Adults Mage = 43.5 (11.7) 79.7% female |
143 | Psychological distress | Lessons completed (+) |
| Bruehlman-Senecal et al., 2020, USA (37) | RCT | Nod (Positive psychology, Mindfulness-based self-compassion, CBT) | No module information / 4 weeks | No mental health-related inclusion criteria. | 1st year college students. Mage = 18.7 (0.33) 51% female |
100 | Loneliness | App pages visited (ns) Social challenges completed (+) Reflections accessed (ns) |
| Calear et al., 2013; Australia (38) | Secondary analysis | MoodGym (CBT) | 5 modules / 9 weeks | No mental health-related inclusion criteria. | School children Mage = 14.56 (0.68) 63.1% female |
530 | Anxiety (general) Depression |
Exercises completed (ns for both outcomes) |
| Casey et al., 2017; Australia (39) | RCT | Improving the Odds (CBT) | 6 modules / 6 weeks | Fulfill diagnostic criteria for gambling disorder. | Adults Mage = 14.56 (0.68) 79.7% female |
60 | Gambling cognitions | Sessions completed (+) |
| Forand et al., 2017, Netherlands (40) | Secondary analysis | Color Your Life (CBT) | 9 sessions / 9 weeks | Mild to moderate symptoms of depression; based on self-report. | Adults Mage = 44.7 (11.3) |
200 | Depression | Modules completed (+) |
| Heckendorf et al., 2019, Germany (41) | RCT | GET.ON Gratitude (Gratitude) | 5 modules / 5 weeks | Elevated levels of repetitive negative thinking; based on self-report. | Adults Mage = 42.3 (10.6) 54.5% female |
132 | Repetitive negative thinking | Activities completed (+) |
| Hensel et al., 2019, Canada (42) | RCT | Big White Wall (BWW) | No module information / 13 weeks (3 months) | Attending outpatient mental health programs. No diagnostic information. | Adults Mage = 41.5 (13.4) 73% female |
542 | Psychological recovery | No. of logins (ns) |
| Krieger et al., 2019, Switzerland (43) | RCT | Mindfulness-Based Compassionate Living (MBCL) | 7 modules / 8 weeks | Elevated levels of self-criticism; based on self-report. | Adults Mage = 38.0 (12.0) 84.7% female |
59 | Self-compassion | Modules completed (+) Time spent in program (ns) |
| Levin et al., 2016, USA (44) | RCT | Acceptance and Commitment Training on College Life (ACT-CL) | 2 modules / 3 weeks | No mental health information. | Young adults (college students) Mage = 21.6 (5.48) 76.9% female |
110 | Psychological distress | Sessions completed (ns) No. of logins (ns) Response to exercises (ns) |
| Luo et al., 2021, China (45) | RCT | eBody Project | 6 modules / 6 weeks | Body dissatisfaction; based on self-report | Youths and young adults M = 17.36 (1.37) 100% female |
191 | Body dissatisfaction | Sessions completed (ns) |
| Twomey et al., 2014, Ireland (46) | RCT | MoodGym (CBT) | 6 modules / 4 weeks | Self-reported symptoms of stress, anxiety, or depression | Adults Mage = 37.3 (10.9) 89.3% female |
80 | Psychological distress | Sessions completed (ns) |
| Wilson et al., 2018, USA (47) | RCT | Goalistics Chronic Pain Management Program (CBT) | 2 h per week / 8 weeks (No. modules not stated) | Patients with chronic non-cancer pain and receiving treatment for opioid use | Adults Mage = 45.5 (12.4) 48.4% female |
31 | Pain self-efficacy | Activities completed (+) |
| Wilson et al., 2018, USA (48) | RCT | Think Clearly About Depression (CBT) | 14 modules / 8 weeks | Self-reported symptoms of depression of moderate severity | Adults Mage = 45.7 (12.8) 91% female |
22 | Depression | Activities completed (ns) |
| Zeng et al., 2020, China (49) | Secondary analysis | Run4Love (CBT) | 65 activities / 12 weeks | Individuals with HIV with self-reported elevated symptoms of depression | Adults Mage = 28.0 (5.8) 5.3% female |
150 | Depression | Item completion rate (+) Frequency of items completed (+) Time spent (ns) |
| Guided interventions (14 studies) | ||||||||
| Ben-Zeev et al., 2018, USA (50) | RCT | FOCUS (CBT) | 12 weeks | Fulfill diagnostic criteria for schizophrenia-related, bipolar, or depressive disorder. | Adults Mage = 49.0 (9.8) 42% female |
82 | Psychological recovery | Weeks completed (+) |
| Berger et al., 2014; Switzerland (51) | RCT | Internet-Based Self-Help (CBT) | 8 sessions / 8 weeks | Fulfill diagnostic criteria for anxiety-related disorders. | Adults Mage = 34.7 (11.3) 56.8% female |
88 | Anxiety (general) | Sessions completed (+) |
| Cillessen et al., 2020, Netherlands (52) | Secondary analysis | Mindfulness-based cognitive therapy (MCBT) | 9 sessions / 9 weeks | Cancer patients with mild psychological distress; based on self-report. | Adults Mage = 52.0 (10.2) |
125 | Psychological Distress | Exercises completed (+) Emails sent (ns) Mean time logged in (ns) Total time logged in (ns) No. of logins (ns) |
| El Alaoui et al., 2013, Sweden (53) | Secondary analysis | ICBT | 10 modules / 10 weeks | Fulfill diagnostic criteria for panic disorder. | Adults Mage = 33.8 (9.7) |
50 | Anxiety (panic disorder) | Modules completed (ns) |
| Hedman et al., 2015, Sweden (54) | Secondary analysis | ICBT (CBT) | 12 modules / 12 weeks | Fulfill diagnostic criteria for hypochondriasis. | Adults Mage = 41.7 (13.6) 85% female |
79 | Anxiety: health-related | Modules completed (+) |
| Hedman et al., 2013, Sweden (55) | Secondary analysis | ICBT (CBT) | 12 modules / 12 weeks | Fulfill diagnostic criteria for hypochondriasis. | Adults Mage = 39 (9.7) 74% female |
81 | Anxiety: health-related | Modules completed (+) |
| Lenhard et al., 2017, Sweden (56) | RCT | BiP for OCD (CBT) | 12 chapters / 12 weeks | Fulfill diagnostic criteria for OCD. | Youth Mage = 15.0 (1.66) 41% female |
33 | OCD severity | Chapters completed (ns) |
| Lundgren et al., 2016, Sweden (57) | RCT | ICBT (CBT) | 7 modules / 9 weeks | Mild to moderate symptoms of depression; based on self-report | Adults Mage = 63.6 (13.9) 60% female |
25 | Depression | Modules completed (ns) No. of logins (+) |
| Moberg et al., 2019, USA (58) | RCT | Pacifica (CBT, Mindfulness) | 35 lesson-activity pairs / 5 weeks | Self-reported, mild to moderate symptoms of depression or anxiety. | Adults Mage = 30.2 (10.9) 75% female |
253 | Depression Anxiety |
No. logins (ns for both) Activities completed (ns for both) |
| Norlund et al., 2018, Sweden (59) | RCT | ICBT | 10 modules / 14 weeks | Patients with myocardial infarction with mild symptoms of depression or anxiety. | Adults Mage = 58.4 (9.0) 37.6% female |
117 | Psychological distress | Homework assignments completed (ns) |
| Schlosser et al., 2018, USA (60) | RCT | PRIME (personalized real-time intervention for motivational enhancement; CBT) | NA / 12 weeks (at least 1 login per week) | Meet criteria for schizophrenia- related disorders | Adults Mage = 24.3 (2.6) 40% female |
22 | Motivation in schizophrenia | No. coach interactions (ns) No. peer interactions (ns) Goals completed (ns) |
| Spence et al., 2017, Australia (61) | RCT | BRAVE-Online (CBT) | 10 sessions / 10 weeks | Meet criteria for social anxiety disorder. | Children and youth Mage = 11.0 (2.57) 62.1% female |
95 | SAD diagnostic severity | Sessions completed (ns) |
| Stjerneklar et al., 2019, Denmark (20) | Secondary analysis | ChilledOut Online (CBT) | 8 modules / 14 weeks | Meet criteria for an anxiety disorder. | Youth Mage = 15.2 (1.33) 78% female |
64 | Anxiety | Modules completed (ns) |
| Todd et al., 2014, UK (62) | RCT | Living With Bipolar (LWB; CBT) | 15 modules / 12 weeks | Self-reported symptoms of bipolar disorder. | Adults Mage = 42.0 (10.4) 74% female |
59 | Quality of life (bipolar disorder) | Modules completed (ns) |
| Guided and unguided interventions (4 studies) | ||||||||
| Fuhr et al., 2018, Germany (63) | Secondary analysis | Deprexis (CBT) | 10 modules / 12 weeks | Mild to moderate symptoms of depression; based on self-report. | Adults Mage = 42.8 (11.0) 68.8% female |
485 | Depression | Sessions completed (+) Time spent (+) |
| Levin et al., 2021, USA (64) | RCT | Online Acceptance Commitment Therapy (ACT) | 12 sessions / 6 weeks | Psychological distress; based on self-report. | Young adults (college students) with self-reported Mage = 22.3 (5.08) 72.4% female |
136 | Psychological distress | Sessions completed (ns) |
| Mira et al., 2017, Spain (65) | RCT | Sonreír es Divertido (Cognitive therapy, positive psychology) | 8 modules / 12 weeks | Mild to moderate symptoms of depression; based on self-report | Adults Mage = 35.2 (9.7) 65% female |
80 | Depression | Modules completed (+) |
| Oromendia et al., 2016, Spain (66) | RCT | Free from Anxiety (CBT) | 8 modules / 8 weeks | Meet criteria for panic disorder. | Adults Mage = 39.4 (8.5) 73.1% female |
52 | Anxiety (panic disorder) | Modules completed (+) |
+Greater engagement associated with post-intervention mental health improvements.
ns, no association between engagement measure and post-intervention symptoms.