Table 1.
Results of Randomized Controlled Trials Concerning Internet-Based Cognitive-Behavioral Therapy (CBT) Interventions
| Reference (Country) | Study Design | Online Therapy Program and Depression and Anxiety Scales Used | Results | Patient Dropout/Completion |
| Clarke et al51 (United States) | RCT of Internet CBT (n = 144) vs a no-access control group (n = 155); subjects with and without depression were randomly assigned to each group | CBT intervention comprising self-guided interactive tutorials with no therapist support (ODIN); scale: CES-D | No difference between the control group and the intervention group; no change in health care utilization in the 12 mo following randomization | Completion rates were 53%, 65%, 66%, and 59% at 4, 8, 16, and 32 wk postrandomization |
| Christensen et al52 (Australia) | RCT of reductions in depression score with Internet-based CBT (n = 182) vs Internet-based psychoeducation (n = 166) vs an attention-control condition (n = 178) | MoodGYM CBT site vs BluePages educational Web site; scale: CES-D | Mean effect sizes for the intent-to-treat population of the CBT and psychoeducation groups were moderate (d = 0.4 for both); mean effect sizes for study completers were moderate: CBT, d = 0.6 and psychoeducation, d = 0.4; mean effect sizes for study completers with CES-D depression scores > 16 were large: CBT, d = 0.9 and psychoeducation, d = 0.8 | 79% of subjects completed the study |
| Griffiths et al20 (Australia) | RCT of stigmatized beliefs associated with depression after Internet-based CBT (n = 182) vs Internet-based psychoeducation (n = 166) vs an attention-control condition (n = 178) | MoodGYM CBT site vs BluePages educational Web site; scale: NA | Use of either site significantly reduced personal stigma compared with the control group: CBT, P = .036 and psychoeducation, P = .031; use of the CBT site significantly increased perceived stigma (P = .004) | 79% of subjects completed the study |
| Andersson et al53 (Sweden) | RCT of Internet-based therapy (n = 36) vs a discussion-only control group (n = 49) | 8-week, 5-module online CBT intervention for depression and anxiety with e-mail feedback from a therapist; scales: BAI, BDI, MADRS | Moderate-to-large mean effect sizes were found for improvements in depression and anxiety: BDI, d = 0.9; MADRS, d = 0.8; and BAI, d = 0.5; improvements in patients' scores were largely maintained at the 6-mo follow-up | 16% had withdrawn at 6-mo follow-up |
| Clarke et al54 (United States) | Three-arm RCT with a no-access usual-treatment group (n = 100) vs subjects using an Internet CBT site with postcard reminders (n = 75) vs subjects using the same Internet CBT site with telephone reminders (n = 80) | CBT intervention comprising self-guided interactive tutorials with telephone or postcard reminders (ODIN); scale: CES-D | Mean effect sizes for reductions in depression symptoms for subjects who received either a postcard or telephone reminders were small but statistically significant compared with the control group: d = 0.3, P = .03; mean effect sizes for intervention subjects with severe depression: d= 0.5, P = .02 | Follow-up completion rates were 64%, 68%, and 66% at 5, 10, and 16 wk postrandomization |
| Spek et al55 (various) | Meta-analysis of 12 RCTs (N = 2,334) | Internet-based CBT for depression and anxiety; scales : BAI, BDI, CES-D, DASS, LSAS-SR, MADRS, STAI-S | Mean effect sizes for reductions in anxiety and depression symptoms were large (d = 1.0) and small (d = 0.3), respectively; mean effect size for Internet CBT with therapist support was large (d = 1.0); CBT without support had a small mean effect size (d = 0.2 to 0.3) | 3%–34% of patients dropped out of the studies included in the meta-analysis |
| Mackinnon et al56 (Australia) | Long-term follow-up of an RCT for reductions in depression scores following Internet-based CBT (n = 94) vs Internet-based psychoeducation (n = 107) vs an attention-control condition (n = 124) | MoodGYM CBT site vs BluePages educational Web site; scale : CES-D | Both CBT and education sites significantly reduced symptoms of depression compared with the control condition (P < .0001 and P < .005, respectively); at 12-mo follow-up, subjects in the CBT group and education site group maintained significant reductions in depression scores vs the control group (P = .044 and P = .024, respectively) | CBT site, 48%; education site, 35%; control group, 30% |
| Spek et al57 (the Netherlands) | 1-year RCT of the effects of Internet-based CBT (n = 102) vs group CBT (n = 99) vs a waiting-list control group (n = 100) in patients aged > 50 y with subthreshold depression | 8-module online CBT intervention for depression and anxiety with no professional support; scale : BDI | Mean effect size for Internet-based CBT was large (d = 1.22); mean effect sizes for group CBT and the waiting-list group were moderate (d = 0.6 and 0.7, respectively) | 48.3% of subjects completed the online course |
| van Straten et al58 (the Netherlands) | RCT of Internet problem-solving therapy for depression, anxiety, and work-related stress (n = 107) vs a waiting-list control group (n = 106) | 5 wk of therapy with weekly explanatory e-mails and feedback from master's level psychology students; scales : CES-D, HADS, MDI, SCL-A | Mean effect sizes were small to moderate for patients in the intent-to-treat population who received therapy vs the control group: CES-D, d = 0.50; MDI, d = 0.33; HADS, d = 0.33; SCL-A, d = 0.42; mean effect sizes were moderate for subjects who completed therapy vs the control group: CES-D, d = 0.67; MDI, d = 0.56; HADS, d = 0.48; SCL-A, d = 0.51 | 55% of subjects in the therapy group completed treatment |
| de Graaf et al59 (the Netherlands) | RCT of online CBT (n = 100) vs online CBT combined with usual care (n = 100) | Online multimedia computerized program (Colour Your Life); scale : BDI-II | Positive expectations and completing > 4 sets of CBT homework were significantly associated with depressive improvement over 9 mo (P < .05 for both) | 11% of participants had dropped out of the study at 9 mo |
Abbreviations: BAI = Beck Anxiety Inventory, BDI = Beck Depression Inventory, CES-D = Center for Epidemiologic Studies Depression Scale, DASS = Depression Anxiety Stress Scale, HADS = Hospital Anxiety and Depression Scale, LSAS-SR = Liebowitz Social Anxiety Scale self-report version, MADRS = Montgomery-Asberg Depression Rating Scale, MDI = Major Depression Inventory, NA = not applicable, ODIN = Overcoming Depression on the Internet study, RCT = randomized controlled trial, SCL-A = Symptom Checklist-Anxiety, STAI-S = State Trait Anxiety Inventory-State Scale.