This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in the Journal of Medical Internet Research, is properly cited. The complete bibliographic information, a link to the original publication on http://www.jmir.org/, as well as this copyright and license information must be included.
Face-to-face cognitive behavioral therapy (CBT) and interpersonal psychotherapy (IPT) are both effective treatments for depressive disorders, but access is limited. Online CBT interventions have demonstrated efficacy in decreasing depressive symptoms and can facilitate the dissemination of therapies among the public. However, the efficacy of Internet-delivered IPT is as yet unknown.
This study examines whether IPT is effective, noninferior to, and as feasible as CBT when delivered online to spontaneous visitors of an online therapy website.
An automated, 3-arm, fully self-guided, online noninferiority trial compared 2 new treatments (IPT: n=620; CBT: n=610) to an active control treatment (MoodGYM: n=613) over a 4-week period in the general population. Outcomes were assessed using online self-report questionnaires, the Center for Epidemiological Studies Depression scale (CES-D) and the Client Satisfaction Questionnaire (CSQ-8) completed immediately following treatment (posttest) and at 6-month follow-up.
Completers analyses showed a significant reduction in depressive symptoms at posttest and follow-up for both CBT and IPT, and were noninferior to MoodGYM. Within-group effect sizes were medium to large for all groups. There were no differences in clinical significant change between the programs. Reliable change was shown at posttest and follow-up for all programs, with consistently higher rates for CBT. Participants allocated to IPT showed significantly lower treatment satisfaction compared to CBT and MoodGYM. There was a dropout rate of 1294/1843 (70%) at posttest, highest for MoodGYM. Intention-to-treat analyses confirmed these findings.
Despite a high dropout rate and lower satisfaction scores, this study suggests that Internet-delivered self-guided IPT is effective in reducing depressive symptoms, and may be noninferior to MoodGYM. The completion rates of IPT and CBT were higher than MoodGYM, indicating some progress in refining Internet-based self-help. Internet-delivered treatment options available for people suffering from depression now include IPT.
International Standard Randomized Controlled Trial Number (ISRCTN): 69603913; http://www.controlled-trials.com/ISRCTN69603913 (Archived by WebCite at http://www.webcitation.org/6FjMhmE1o)
Depression is a highly prevalent mental disorder [
Both CBT and IPT require significant therapist time. Long waiting lists caused by low workforce numbers are common [
The present study examined the effectiveness of Internet-delivered IPT and a new Internet-delivered CBT module (from e-couch [
This automated, 3-arm, fully self-guided, online noninferiority trial compared 2 new treatments (IPT and CBT) to an active control treatment (MoodGYM) for depressed individuals. The Internet-delivered CBT and IPT interventions (from e-couch) were developed at the Centre for Mental Health Research (CMHR) at the Australian National University (ANU). The e-couch program targets a range of conditions currently (depression, generalized anxiety disorder, social anxiety disorder) with other conditions to be added in the future. It also provides modules for bereavement and loss, as well as divorce and separation. It comprises a mental health literacy component and psychotherapeutic components for each condition (eg, CBT, IPT, applied relaxation, physical activity, and behavioral activation for depression). This study compared the IPT and CBT components with the 4-module version of MoodGYM. To increase external validity, there was no specific promotion for the trial. Spontaneous visitors from around the world who registered on the e-couch Internet website [
Participants were randomly assigned to MoodGYM, CBT, or IPT, stratified by sex, age, and presenting depression symptom severity. The randomization schedule for participant allocation to condition groups was prepared by using an automated system built into the trial software, and randomization occurred automatically. The allocation sequence was concealed from the researchers. Participants randomized to the intervention groups were aware of the allocated arm. Following randomization, an automated email containing log-in details for the assigned program was sent to each participant, at which point the intervention could be accessed immediately.
All programs were offered over 4 weeks. Users were required to complete the modules in order. Participants were able to revisit previous pages of the modules and scores of previous assessments, but were not able to repeat the assessments. Each week an automated email was sent to advise participants of the availability of their new module. Participants were always offered the option to pause and restart at their chosen time. See
The Internet-delivered CBT intervention comprised 1 component of the depression stream of e-couch [
The Internet-delivered form of IPT comprised 1 component of the depression stream of e-couch [
The online CBT package comprised a 4-module version of MoodGYM [
All questionnaires comprised online standard self-report measures taken at baseline (pretest), immediately after the intervention (posttest), and 6 months after the intervention (follow-up). Measures of participant characteristics were collected at baseline, symptoms measures were administered at all 3 time points, and user satisfaction was collected at posttest.
The survey included questions concerning sociodemographic characteristics (age, gender, country of origin, location, and education level), previous history of depression, previous use of treatments for depression, marital status, preference for randomization condition, perceived need for treatment, and current medication.
The 20-item self-report CES-D was used to assess depressive symptoms (item score: 0-3; total score range: 0-60) [
The Client Satisfaction Questionnaire (CSQ-8) assesses global client satisfaction with treatments [
Preference for randomization condition was assessed by asking the question “Do you have a preference to be in one of the programs?” at baseline. Participants replied with no preference or “yes, program 1, 2, 3.” These data were included in the analyses (no preference, preference: match/no match).
Adherence was measured in 2 ways for each individual: (1) completion of posttest surveys (all groups), and (2) the number of IPT, CBT, or MoodGYM modules completed.
Noninferiority trials require the a priori specification of a noninferiority margin. We used the confidence interval (CI) approach [
The null hypothesis is rejected to claim noninferiority of the standard control treatment and the new treatment, if
Data integrity (distribution, outliers, skewness, and kurtosis) tests were conducted. Measures of skewness and kurtosis indicated deviations from normality for baseline CES-D scores because of some extreme responses. The Box-Cox model omitting the pretest scores was fitted and the transformed data were compared with the raw data using mixed model analyses. For ease of interpretation of the test results, only raw data are reported because the conclusions were the same. The baseline characteristics of the 3 groups were compared by using 1-way analysis of variance (ANOVA), and Kruskal-Wallis and Mann-Whitney U tests for continuous measures and chi-square (χ2) tests for categorical variables.
In noninferiority trials, intention-to-treat (ITT) analysis will often increase the risk of falsely claiming noninferiority (type I error) [
Between-group and within-group effect sizes were calculated according to Cohen’s
Screenshot of e-couch cognitive behavior therapy (CBT) website.
Screenshot of e-couch interpersonal psychotherapy (IPT) website.
Screenshot of MoodGYM website.
Formula of Mascha and Sessler.
Of the 10,598 individuals who registered on e-couch during the trial period, 5796 expressed interest in the trial and proceeded to screening. Of these, 3166 did not meet the eligibility criteria (eg, under 18 years of age or currently receiving treatment for depression by a mental health specialist) and were excluded from the study. Of the remaining 2630 participants, 2045 provided informed consent; however, 116 of these did not subsequently verify their email address. Accordingly, a total of 1929 participants were randomized to 1 of the 3 conditions. However, 66 of these participants were excluded after randomization because it became apparent that they were ineligible at baseline for participation (eg, being a researcher or a student, n=21). In addition, 45 randomized participants did not complete the baseline assessment. This was missed at first screening because of a technical fault, but was picked up subsequently.
Of the total sample (N=1843), 543 (29.46%) were aged between 25 to 29 years, and most were female, (1334/1843, 72.38%). Participants were primarily Australian or New Zealand residents (751/1843, 40.75%) and most were well educated, having completed postsecondary education (1606/1843, 87.14%). The mean CES-D baseline score was 36 (SD 11.52). There were no significant differences between the groups at baseline with respect to depressive symptoms (χ2
2= 3.1,
In total, 30% (549/1843) of participants completed the posttest assessment and 28% (336/1843) completed the follow-up assessment. Of participants who were adherent to the program (completed 50% or more of the modules), 25.8% (476/1843) and 16% (294/1843) completed posttest and follow-up assessments, respectively. Of the IPT participants, 49.5% (307/620) completed at least half of the intervention (≥2 modules) and 27.3% (169/620) completed all modules. For the CBT participants, 37.7% (230/610) finished 2 or more modules and 14.4% (88/610) completed all modules. A total of 195 of 613 participants (31.8%) finished half or more of the MoodGYM program. Of these, 10.9% (67/613) finished the whole program. Reasons given for dropout included technical problems, personal issues (lack of time), disease-specific barriers (feeling too depressed to work on the program or not convinced that the program would help), general intervention problems (programs was taking too long, too much text to read, boring, or too repetitive), specific intervention issues (the examples were not relevant to the participant), or engagement issues (preferred to obtain help from somewhere other than a computer). However, most participants (1248/1294, 96%) did not provide any reason for dropout. Those who dropped out of treatment had significantly higher scores on the CES-D (χ2
1=4.3,
Results are presented for 3 groups: all participants (all those enrolled in the trial, ITT), completers (those completing online surveys at posttest and at 6-month follow-up), and adherent completers (those completing ≥50% of the modules).
For completers, the within-group effect sizes on the primary outcome measure CES-D were large for all treatments at posttest (IPT
The previously determined noninferiority margin (
Residuals of the models were inspected and showed nonnormality. Therefore, to be thorough, power transforms were estimated fitted using a Box-Cox model that included the same terms as the mixed model omitting the pretest scores. The test of deviations of residuals from normality was significant for just the IPT group at posttest (
Baseline demographic, socioeconomic, and clinical characteristics of participants for the e-couch cognitive behavioral therapy (CBT), the e-couch interpersonal psychotherapy (IPT), and the MoodGYM website.
Condition | All participants | MoodGYM | CBT | IPT | |
n/N (%) | 1843 (100) | 613 (33.26) | 610 (33.10) | 620 (33.64) | |
Female, n (%) | 1334 (72.38) | 438 (71.45) | 445 (72.95) | 451 (72.74) | |
|
|
|
|
|
|
|
18-24 | 307 (16.66) | 100 (16.31) | 92 (15.08) | 115 (18.55) |
|
25-34 | 543 (29.46) | 181 (29.52) | 188 (30.82) | 174 (28.06) |
|
35-44 | 470 (25.50) | 145 (23.65) | 164 (26.88) | 161 (25.97) |
|
45-55 | 338 (18.34) | 111 (18.11) | 113 (18.52) | 114 (18.39) |
|
>55 | 185 (10.04) | 76 (12.39) | 53 (8.69) | 56 (9.03) |
|
|
|
|
|
|
|
Australia and New Zealand | 751 (40.75) | 254 (41.44) | 239 (39.18) | 258 (41.61) |
|
United Kingdom | 454 (24.63) | 148 (24.14) | 157 (25.73) | 149 (24.03) |
|
United States | 350 (18.99) | 112 (18.27) | 115 (18.85) | 123 (19.84) |
|
Canada | 100 (5.43) | 28 (4.57) | 36 (5.90) | 36 (5.81) |
|
Other | 188 (10.20) | 71 (11.58) | 63 (10.32) | 54 (8.71) |
Spouse | 914 (49.59) | 301 (49.10) | 310 (50.82) | 303 (48.87) | |
|
|
|
|
|
|
|
None, or primary | 21 (1.13) | 11 (1.79) | 4 (0.66) | 6 (0.97) |
|
Secondary | 216 (11.72) | 70 (11.42) | 67 (10.98) | 79 (12.74) |
|
Postsecondary | 1606 (87.14) | 532 (86.79) | 539 (88.36) | 535 (86.29) |
Baseline CES-Da, mean (SD) | 36.01 (11.52) | 35.34 (11.61) | 36.29 (11.04) | 36.38 (11.86) | |
Current medicationb, n (%) | 754 (40.91) | 253 (41.27) | 255 (41.80) | 246 (39.68) |
aCES-D: Center for Epidemiological Studies Depression scale.
bAny prescribed current medication.
Flowchart of participants.
Results and effect sizes (Cohen’s
Program | Test time, n; mean (SD) | Within-group effect size, |
Between-group effect size, |
|||||||
|
Pretest | Posttest | Follow-up | Pre-post | Pre–follow-upa | Program | Posttest | Follow-up |
||
|
|
|
|
|
||||||
|
IPT | 206; 35.65 (11.85) | 206; 26.22 (12.92) | 129; 22.41 (13.84) | 0.76 (0.56,0.96) | 1.02 (0.76,1.28) | IPT vs MoodGYM | 0.14 (–0.06,0.35)b | 0.18 (–0.09,0.45)b | |
|
CBT | 181; 34.46 (11.31) | 181; 23.68 (13.34) | 115; 18.17 (12.15) | 0.87 (0.65,1.0 9) | 1.44 (1.15,1.72) | CBT vs MoodGYM | 0.05 (–0.17,0.26)c | 0.12 (–0.15,0.39)c | |
|
MoodGYM | 162; 35.19 (12.44) | 162; 24.30 (14.10) | 92; 19.79 (14.92) | 0.82 (0.59,1.04) | 1.04 (0.72,1.34) |
|
|||
|
|
|
|
|
||||||
|
IPT | 192; 35.60 (11.79) | 192; 26.38 (13.25) | 119; 22.50 (13.55) | 0.74 (0.53,0.94) | 1.02 (0.74,1.28) | IPT vs MoodGYM | 0.23 (0.0,0.46)b | 0.31 (0.02,0.60)b | |
|
CBT | 158; 34.30 (11.79) | 158; 23.09 (13.25) | 101; 17.75 (13.55) | 0.89 (0.65,1.11) | 1.33 (1.02,1.63) | CBT vs MoodGYM | 0.02 (–0.25,0.22)c | 0.04 (–0.26,0.34)c | |
|
MoodGYM | 126; 34.41 (11.32) | 126; 23.33 (13.25) | 74; 18.30 (13.55) | 0.90 (0.64,1.16) | 1.21 (0.86,1.56) |
|
|||
|
|
|
|
|
||||||
|
IPT | 620; 36.38 (11.51) | 620; 26.59 (20.27) | 620; 23.17 (25.60) | 0.59 (0.48,0.71) | 0.67 (0.55,0.78) | IPT vs MoodGYM | 0.09 (–0.02,0.21)b | 0.09 (–0.02,0.21)b | |
|
CBT | 610; 36.29 (11.51) | 610; 24.80 (21.34) | 610; 19.68 (26.85) | 0.67 (0.55,0.79) | 0.80 (0.69,0.92) | CBT vs MoodGYM | 0.01 (–0.10,0.12)b | 0.03 (–0.08,0.14)c | |
|
MoodGYM | 613; 35.34 (11.52) | 613; 24.58 (22.43) | 613; 20.56 (29.69) | 0.60 (0.49,0.72) | 0.66 (0.54,0.77) |
|
aWithin-group follow-up effect size for completers is based upon the following pretest scores: IPT (n=129, mean 35.66, SD 12.05); CBT (n=115, mean 34.89, SD 11.05); MoodGYM (n=92, mean 34.13, SD 12.65); within-group follow-up effect size for adherent completers is based upon the following pretest scores: IPT (n=119, mean 35.48, SD 11.91); CBT (n=101, mean 34.68, SD 11.90); MoodGYM (n=74, mean 33.77, SD 11.92).
bIn favor of MoodGYM.
cIn favor of CBT.
Effectiveness of Internet-delivered programs with depression score (CES-D) as dependent variable.
Depression score | Posttest | Follow-up | |||||||
|
Time | Group×time | Time | Group×time | |||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Completers | 290.309 (2,434.0) | <.001 | 1.15 (4,436.3) | .33 | 237.187 (2,315.1) | <.001 | 1.20 (4,315.3) | .31 |
|
Adherent completers | 260.021 (2,386.7) | <.001 | 1.52 (4,388.3) | .20 | 216.083 (2,284.1) | <.001 | 1.426 (4,284.5) | .23 |
|
Intention-to-treat | 382.60 (2,484.155) | <.001 | 1.45 (4,483.246) | .22 |
|
<.001 |
|
|
|
|
|
|
|
|
|
|
|
|
|
Completers | 306.190 (2,368.8) | <.001 | .976 (4,369.4) | .42 | 223.572 (2,242) | <.001 | 0.824 (4,242) | .51 |
|
Adherent completers | 275.800 (2,327.7) | <.001 | 1.39 (4,328.3) | .24 | 230.990 (2,242.9) | <.001 | 1.056 (4,243.1) | .38 |
|
Intention-to-treat | 306.190 (2,368.8) | <.001 | 0.976 (4,451.2) | .42 |
|
|
|
|
For completers, no significant differences in CSC were found between the 3 programs at posttest (χ2
2=1.78,
Analyses were also undertaken for the subsample of participants who had symptoms severe enough to be considered clinical cases at baseline. A CES-D value of ≥22 is considered to indicate clinical caseness [
There was a significant difference between the 3 interventions in treatment satisfaction scores at posttest for completers as measured with the CSQ-8 (
Proportion of participants reaching the criteria for clinically significant change (score <22) on the Center for Epidemiological Studies Depression scale (CES-D).
Treatment condition | Baseline caseness, n (%) | Clinically significant change | |||
|
|
Posttest |
6-month follow-up |
||
|
|
Completersa | Adherent completersb | Completersc | Adherent completersd |
IPT (n=610) | 581 (95.2) | 61 (32.0) | 55 (32.7) | 54 (43.5) | 49 (48.0) |
CBT (n=620) | 581 (93.7) | 65 (38.2) | 61 (43.6) | 63 (57.3) | 32 (36.0) |
MoodGYM (n=613) | 575 (93.8) | 52 (34.7) | 41 (39.4) | 42 (51.2) | 36 (59.0) |
aCompleters posttest IPT (n=194), CBT (n=170), MoodGYM (n=150).
bAdherent completers posttest IPT (n=168), CBT (n=140), MoodGYM (n=104).
cCompleters 6-month follow-up IPT (n=124), CBT (n=110), MoodGYM (n=82).
dAdherent completers IPT (n=102), CBT, MoodGYM (n=61).
The present study is the first to show that Internet-delivered IPT can be effective in the treatment of depressive symptoms at posttest and at 6-month follow-up. Both the IPT and the CBT online interventions employed in the trial showed significant medium to large within-group effect sizes on the CES-D for completers and adherent completers. For the ITT sample, effect sizes were smaller, but still moderate in size. Of the clinical cases, completers and adherent completers showed medium to large effect sizes on posttest and follow-up ratings. We found that IPT and CBT were noninferior compared to MoodGYM for those who returned posttest, and between-group effect sizes were small. Although recent MoodGYM studies report similar effect sizes to our study, our conclusions need to be taken with some caution given that the effect size found in this study differed from the effect size from the initial study, and therefore might hamper assay sensitivity. Furthermore, the new CBT program reached consistently higher, but not significant, effect sizes compared to the IPT and the standard MoodGYM program. Overall, the between-group effect sizes were larger for IPT versus MoodGYM compared to CBT versus MoodGYM.
Our findings of the equivalent effectiveness of CBT and IPT are concordant with previous research on face-to-face interventions [
The CSC rates in the current study were lower than those reported in other online studies [
There was no significant difference in treatment preference at baseline before randomization. This lack of preference for treatment condition is important, because it suggests that a disparity between the preferred and allocated conditions was unlikely to negatively impact disproportionately on the findings. However, treatment satisfaction ratings were significantly lower for the IPT program compared with MoodGYM and CBT. One explanation for these findings may be related to what people were looking for in an online intervention. Also, although there were no patient program preferences before randomization, it is unknown how participants felt about being randomized to IPT immediately postrandomization but before exposure to the treatment. Online CBT is widely known, whereas fewer individuals know about IPT. To the extent that the social psychological literature has demonstrated that familiarity breeds liking, it may be possible that differences in satisfaction in treatment were driven in part by differences in familiarity with each treatment. Another explanation may be that the IPT program was too brief. Adherence to the treatment was considerably lower than the original MoodGYM trial [
This study has several limitations. First, as mentioned previously, the effect size found in this study differs from that on which we based the noninferiority margin and power calculation. Second, the noninferiority margin of the primary outcome measure is usually based on the lower-bound CI of the between-group effect size of the traditional treatment [
Low adherence, however, could underestimate differences between groups, and therefore increase the likelihood of finding noninferiority. However, our completer analyses revealed no statistical differences in effectiveness between the 3 programs. Nevertheless, our conclusions need to be taken with caution given the high dropout rates. One possible explanation of the difference in attrition rates across the programs might be that MoodGYM takes longer to complete compared with the other programs, and lengthier programs might be associated with greater attrition [
Future research is needed to replicate IPT noninferiority compared to CBT programs, to test whether the new CBT program is superior to other programs, to examine whether guided Internet-delivered IPT is as effective as face-to-face IPT, to investigate methods to improve adherence, to investigate whether IPT would also be effective outside of a randomized controlled trial setting, and whether Internet-delivered IPT is also effective in the treatment of other disorders, such as social phobia or panic disorder. It is important that future research investigates individual characteristics, such as recent life events, that predict treatment response for IPT. There will also be value in investigating whether a planned extended version of e-couch IPT will yield higher satisfaction ratings.
Although a firm conclusion regarding the noninferiority of IPT and the sustainability of results compared to CBT cannot be drawn yet, we can conclude that Internet-delivered IPT is an effective treatment for depressive symptoms, and thereby offers those with depression another online treatment option. An Internet-accessed IPT program could potentially be more appealing to IPT-trained therapists than a CBT-based one, perhaps making such clinicians more likely to recommend it to their clients. In the United Kingdom, the first wave of the Increasing Access to Psychological Therapies (IAPT) initiative was CBT only, but recently it has been expanded to other approaches, including IPT. Given that MoodGYM is already a resource used within IAPT (mostly without support), Internet-delivered IPT could well be a feasible option in second-wave IAPT services. Furthermore, the new e-couch CBT program was shown to be noninferior to the active CBT-based control program and thus may provide an open-access alternative to MoodGYM. Another important finding is that the completion rates of the new treatments were higher, indicating some progress in refining Internet-based self-help.
CONSORT-EHEALTH checklist V1.6.2 [
Mean depression scores over time for interpersonal psychotherapy (IPT), cognitive behavior therapy (CBT), and MoodGYM (intention-to-treat, N=1843).
Results and effect sizes (Cohen's
The Australian National University
cognitive behavioral therapy
Center for Epidemiological Studies Depression scale
Centre for Mental Health Research
clinically significant change
Client Satisfaction Questionnaire
Increasing Access to Psychological Therapies
interpersonal psychotherapy
intention-to-treat
linear mixed model
missing at random
reliable change index
Web Screening Questionnaire
This study was funded by the Faculty of Psychology and Education of the VU University, Amsterdam, and the Center for Mental Health Research at The Australian National University. HC is supported by NHMRC Fellowship 525411. KG is supported by an NHMRC Senior Research Fellowship No 525413. We wish to thank Ada Tam, Philip Batterham, Jos Twisk, Bob Forrester, Filip Smit, and Lisanne Warmerdam for their helpful comments and participation in the project.
The interventions investigated in the current study were developed at the Centre for Mental Health Research, The Australian National University. HC and KG are authors and developers of the MoodGYM and e-couch websites, but derive no personal or financial benefit from their operation.