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Table 2 Study characteristics

From: eHealth interventions for the prevention of depression and anxiety in the general population: a systematic review and meta-analysis

Study Sample/eligibility Conditions Support Intervention Follow-up period (rate) Outcome Conclusions Quality assessment
Buntrock et al. [41, 42] N = 406; German general pop. (no MDD on SCID).
Aged 18+ years
(73.9% female)
i. iCBT
ii. Psychoed.
Automated SMS reminders, 2 h online trainer feedback 6 × 30 min sessions (3–6 weeks). Behavioural and problem-solving therapy. 6 weeks (90.1%)
6 months (80.0%)
12 months (82.3%)
Mean sessions: 5.84
Symptom reduction (CES-D). MDD incidence. 6-week BG ES: Cohen’s d = 0.69 (F1,403 = 54.104, p < .001).
6-month BG ES: Cohen’s d = 0.28 (F1,402 = 9.240, p = .003).
There was a significant difference in MDD incidence rates over 12 months favouring the intervention group (hazard ratio = 0.59, 95% CI: 0.42–0.82; p = .002).
23
Christensen et al. [43] N = 558; Australian Internet users (No anxiety disorder on MINI).
Aged 18–30 years
(80.6% female)
i. iCBT + Psychoed. (A)
ii. A + telephone reminders
iii. A + email reminders
iv. Placebo website (B)
v. B + telephone reminders
Differing reminder conditions, 2-min/week. No therapeutic content. 10 × 10 weekly sessions. Mindfulness-focussed CBT for anxiety (e-couch). 10 weeks (64.5%)
6 months (54.3%)
12 months (47.3%)
Mean sessions: (i) 3.7; (ii) 7.3; (iii) 5.5; (iv) 3.7; (v) 8.3.
Symptom reduction (GAD-7).
GAD incidence.
Significant time effects for each of the three follow-ups. No significant group × time effects for any comparison. Overall, indicated prevention of GAD was deemed not effective 21
Clarke et al. [46] Relevant subgroup: n = 63; US HMO member adults (CES-D < 20).
Aged 18+ years
(75.6% female)
i. iCBT + Psychoed.
ii. Usual care
No support. 7 chapters. CBT skills program (focusing on the cognitive restructuring techniques). 4 weeks (52.8%)
8 weeks (65.2%)
16 weeks (65.5%)
32 weeks (59.2%)
Mean logins: 2.6
Symptom reduction (CES-D). Significant reduction in symptoms in intervention participants compared to control at the 16-week (BG ES: Cohen’s d = 0.17, p < .05) and 32-week (BG ES: Cohen’s d = 0.48, p < .01) follow-up. 16
Cukrowicz et al. [47] N = 152; US undergrad. (BAI ≤ 18; BDI ≤ 19).
95% aged 18–21 years
(73.7% female)
i. Psychoed. + CBT
ii. Psychoed.
Facilitated session. 6 × 20 min segments (1 laboratory session).
Situational analysis-focussed CBT.
2 months (90.3%) Symptom reduction (BAI & BDI). BAI, BG ES: Cohen’s d = 0.24 (F1,145 = 7.84, p < .01).
BDI, BG ES: Cohen’s d = 0.27 (F1,145 = 9.64, p < .01.
Additional significant reductions on PANAS and STAI-S, and Reliable Change Index.
17
Imamura [44, 52] N  =  762; Japanese workers (No past month MDD on WHO-CIDI).
Aged 18+ years
(16.1% female)
i. iCBT
ii. Stress reduction tips email
Email reminders. Homework feedback from clinical psychologist. 6 × 30 min sessions (6 weeks). CBT skills program (self-monitoring, cognitive restructuring, assertiveness, problem solving, and relaxation). 3 months (79.5%)
6 months (77.7%)
12 months (67.1%)
Mean sessions: 4.53
Symptom reduction (BDI-II). MDE incidence. 3-month BG ES: Cohen’s d = −0.14, 95% CI: −0.30 to 0.02 (t 621.35 =   − 1.99, p < .05).
6-month BG ES: Cohen’s d = −0.16, 95% CI: −0.32 to 0.00 (t 621.35 =   − 1.99, p < .05).
12-month BG ES: Cohen’s d = −0.08, 95% CI: −0.26 to 0.09 (t 610.33 =   − 1.42, p = .16).
Significant reduction in MDE incidence in intervention compared to control at 12-month (Log-rank χ 2 = 7.04, p < .01) but not 6-month (Log-rank χ 2 = 3.26, p = .07).
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Levin et al. [48] Relevant subgroup: n  =  43; US undergrad. (DASS in normal range).
Aged 18–21 years (53.9% female)
i. ACT
ii. Waitlist
Email reminders. 2 sessions. Youth-focussed ACT program. 3 weeks (79.5%)
6 weeks (77.7%)a
92% completed program
Symptom reduction (DASS). No significant between group differences were observed on depression, anxiety of stress among the non-distressed subgroup (p > .10). 19
Lintvedt et al. [49] Relevant subgroup: n  =  52; Norwegian undergrad. (subclinical: CES-D).
Aged 18+ years (53.9% female)
i. Psychoed. + iCBT
ii. Waitlist
Weekly automated assignments. 5 weekly modules. CBT, interpersonal therapy, relaxation self-help program (Moodgym) & psychoed. Program (Bluepages) 8 weeks (68.0%)
Mean modules: 2–3
Symptom reduction (CES-D). There was a significant increase in depressive symptoms for the subclinical control group compared to the intervention group (F 1,24 = 6.86, p < .05; Hedges g = 0.61). 22
Morgan et al. [50] N = 1326; English speaking gen. Pop. (subclinical: PHQ-9)
Aged 18–79 years (77.6% female)
i. Self-help emails
ii. Psychoed. emails
No support. 2 emails/week (6 weeks). Persuasive framing, tailoring, goal setting, limiting cognitive load. 3 weeks (54.8%)
6 weeks (42.9%)
95.6% received the emails
Symptom reduction (PHQ-9). There was a small significant difference in depression symptoms in intervention group compared to control (d = 0.17, 95% CI: 0.01 to 0.34). There was a lower, although non-significant, risk of major depression in the active group. 20
Musiat et al. [51] Relevant subgroup: n  =  859; UK tertiary students (low risk on the SURPS).
Aged 18–57 years (70.5% female)
i. iCBT
ii. Student life program
No support. 5 × 30 min modules Personality trait-driven CBT program (PLUS) 6 weeks (49.7%)a
12 weeks (38.3%)
47% completed a module
Symptom reduction (PHQ-9; GAD-7). Significant intervention effects were found in the high risk group but for those at low risk no significant change was detected in PHQ-9 (p > .999) or GAD-7 (p = .415) 21
Spek et al. [40, 45] N = 301; Dutch older general pop. (no MDD on WHO-CIDI).
Aged 50–75 years (63.5% female)
i. iCBT
ii. group CBT
iii waitlist
No support. 8 sessions (8 weeks) Psychoed. and CBT (Coping with depression) 10 weeks (60.1%)
12 months (63.1%)
Mean modules: 5.5
Symptom reduction (BDI-II). Significant intervention effects were found in both intervention groups compared to control. No differences were found between interventions (Internet vs control: post-treatment BG ES: Cohen’s d = 0.55; 12-month BG ES: Cohen’s d = 0.53). 24
  1. MDD major depressive disorder, MDE major depressive episode, Psychoed. psychoeducation, iCBT Internet Cognitive Behavioural Therapy, SCID Structured Clinical Interview for DSM, TAU treatment as usual, MINI Mini-International Neuropsychiatric Interview, HMO Health Maintenance Organization, BDI-II Beck Depression Inventory, BAI Beck Anxiety Inventory, WHO-CIDI World Health Organisation Composite International Diagnostic Interview, PHQ-9 Patient Health Questionnaire, GAD-7 Generalized Anxiety Disorder–7-item scale, BG ES between-group effect size, ACT Acceptance and Commitment Therapy, CES-D Center for Epidemiological Studies-Depression, DASS Depression Anxiety Stress Scale; undergrad. Undergraduate, PANAS Positive and Negative Affect Schedule, STAI-S State-Trait Anxiety Inventory
  2. aResults not reported at this follow-up point