e-terapia: Computer therapy for the anxiety and depression disorders is effective, acceptable and practical health care: An updated meta-analysis

Review

https://www.sciencedirect.com/science/article/pii/S0887618517304474

https://doi.org/10.1016/j.janxdis.2018.01.001 Get rights and content

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Highlights

•: Meta-analysed internet-delivered CBT (iCBT)for depression and anxiety disorders.
•: The mean effect size (g = 0.80, NNT = 2.34) was maintained at follow up after 3–36 months.
•: Face-to-face CBT, iCBT, and bibliotherapy are equally effective.
•: On average, face-to-face therapy requires 7.8 times more therapist time than iCBT.
•: iCBT has high rates of satisfaction and acceptability, and moderate adherence.

Abstract

Background

A 2010 meta-analysis of internet-delivered CBT (iCBT) RCTs argued ‘computer therapy for the anxiety and depressive disorders was effective, acceptable and practical health care’ without data on effectiveness or practicality in routine practice.

Methods

Databases, reviews and meta-analyses were searched for randomised controlled trials of cCBT or iCBT versus a control group (care as usual, waitlist, information control, psychological placebo, pill placebo, etc.) in people who met diagnostic criteria for major depression, panic disorder, social anxiety disorder or generalised anxiety disorder. Number randomised, superiority of treatment versus control (Hedges’g) on primary outcome measure, length of follow-up, follow up outcome, patient adherence and satisfaction/harm were extracted; risk of bias was assessed. A search for studies on effectiveness of iCBT in clinical practice was conducted.

Results

64 trials were identified. The mean effect size (efficacy) was g = 0.80 (NNT 2.34), and benefit was evident across all four disorders. Improvement was maintained at follow-with good acceptability. Research probity was good, and bias risk low. In addition, nine studies comparing iCBT with traditional face-to-face CBT and three comparing iCBT with bibliotherapy were identified. All three modes of treatment delivery appeared equally beneficial. The results of effectiveness studies were congruent with the results of the efficacy trials.

Limitations

Studies variably measured changes in quality of life and disability, and the lack of comparisons with medications weakens the field.

Conclusions

The conclusions drawn in the original meta-analysis are now supported: iCBT for the anxiety and depressive disorders is effective, acceptable and practical health care.

Keywords

iCBT

Internet-CBT

Cognitive behavioral therapy

Depression

Anxiety

1. Introduction

Major depression and the anxiety disorders are leading causes of disability worldwide, (Whiteford, Ferrari, Degenhardt, Feigin, & Vos, 2015). Pharmacotherapy and psychotherapy have been the mainstay of treatment for anxiety and depression. CBT is the commonest form of psychotherapy for depression and anxiety and has traditionally been delivered face-to-face. Therapist-delivered CBT is difficult to standardise as factors unique to each therapist-patient interaction can alter how and what treatment is delivered. Central elements of CBT can be omitted and each individual provider can introduce “drift” by administering their own personal version of the intervention (Waller, 2009; Shafran et al., 2009).

Computerised CBT (cCBT) was introduced in 1990, in the form of a CBT manual delivered via CD-ROM (Selmi, 1990). By the end of the decade, it was being delivered over the internet (iCBT). iCBT usually takes the form of modules or lessons delivering CBT concepts by desktop, internet or phone app. iCBT has been shown to be equally effective as face-to-face CBT (Andersson, Cuijpers, Carlbring, Riper, & Hedman, 2014), with additional benefits including privacy, convenience and fidelity of treatment. Therapist drift and variability between trial and dissemination in practice is less likely as, once tested and found successful, courses can be distributed exactly as they were designed.

A 2010 meta-analysis, based on 22 randomised controlled trials, argued that computer therapy for the anxiety and depressive disorders was effective, acceptable and practical healthcare (Andrews, Cuijpers, Craske, McEvoy, & Titov, 2010). Since that publication, there have been a number of systematic reviews of this area. Hedman et al. (Hedman, Ljotsson, & Lindefors, 2012) identified iCBT for depression, social anxiety disorder and panic disorder as established treatments. Anderssen et al. (Andersson et al., 2014) identified eight direct comparisons of face to face CBT and iCBT in depression, social anxiety disorder and panic disorder, and found them to be equally efficacious. Olthius, Watt, Bailey, Hayden, and Stewart (2015) (Olthius et al., 2015) did a Cochrane Collaboration of face to face CBT, guided and unguided iCBT and found no differences in efficacy. In addition there have been systematic reviews and meta-analyses looking at trans-diagnostic iCBT for these four disorders (Newby, Twomey, Yuan Li, & Andrews, 2016), and for post-traumatic stress disorder (Sijbrandij, Kunovski, & Cuijpers, 2016).

As the field has matured in the intervening years, we have repeated the Andrews et al. meta-analysis (Andrews et al., 2010) using comparable search terms. We identified studies in which iCBT was compared to a control condition in people who met diagnostic criteria on the basis of structured interviews or above threshold scores on standardised questionnaires. This was done for the same four disorders considered in the 2010 meta-analysis − major depressive disorder (MDD), panic disorder (PD), social anxiety disorder (SAD) or generalised anxiety disorder (GAD). A replication and extension of the original meta-analysis to include an examination of the effect of type of control group and risk of bias on outcome, maintenance of improvement over time, as well as time spent by the therapist, will contribute to the discussion as to whether the original claim that ‘computerised therapy for the anxiety and depressive disorders is effective, acceptable and practical health care’ remains justified.

2. Method

This review was registered (www.ANZCTR.org.au/ACTRN12610000030077.aspx). The protocol for search, extraction and analysis followed the description in the original paper.

2.1. Study selection

Participants must have been aged 18 or over, and met criteria for either major depressive disorder, generalised anxiety disorder, panic disorder with or without agoraphobia or social anxiety disorder as a primary diagnosis. Diagnosis could be determined by a clinician, telephone interview or by meeting a recognised cut-off on a validated self-report questionnaire. Conditions for inclusion were English language randomised controlled trials of iCBT versus either waitlist control (WLC), information control (IC), care as usual (CAU) or placebo. The outcome of interest was change in symptom severity. All papers analysed were either published or in press, and the investigators had copies of all manuscripts. RCTs that compared iCBT vs face-to-face CBT and iCBT vs bibliotherapy were extracted for separate analysis and effect sizes were calculated. Effectiveness studies were identified and reviewed. In addition, a systematic review of the literature was conducted to identify any harms of iCBT.

2.2. Information sources

Papers identified in the search that were published, or available to the authors, before September 2016 were included. Abstracts were identified by combining terms representative of internet-delivered psychological treatment for major depressive disorder, generalised/generalized anxiety disorder, panic disorder (with or without agoraphobia) or social phobia/social anxiety disorder (both MeSH terms and text words). As in the previous study (Andrews et al., 2010), studies of treatments aimed at a range of diagnoses (transdiagnostic studies) were excluded (see Newby (Newby, Twomey et al., 2016) for a recent review), as were studies of depressive or anxiety symptoms in which no data on the probability of satisfying diagnostic criteria were supplied. An example search strategy for Medline is available from the corresponding author, as per PRISMA guidelines (Moher, Liberati, Tetzlaff, & Altman, 2009). The supplementary search consisted of reference lists of reviews and meta-analyses identified as relevant, as well as reference lists of included studies and papers from conferences and other sources.

Data extracted from each study included: number of subjects randomised, details of treatment condition and control group, pre and post means and standard deviations in the principal outcome measure, Hedges’g (Hedges & Vevea, 1996), number needed to treat (NNT) (Kraemer & Kupfer, 2006), adherence and satisfaction/harm. Data was collected for the primary outcome measure(s) named in the study. Adherence was defined as the percentage of participants randomised who finished the course. To analyse risk of bias using the Cochrane Collaboration tool (Higgins et al., 2011), information about sequence generation, allocation concealment, blinding, missing data and selective reporting was also extracted. The extraction of data and the adequacy of bias minimisation was rated independently by two researchers (AB and LE), with differences resolved following discussion with GA.

2.3. Meta-Analysis

We followed both the PRISMA guidelines (Moher et al., 2009) and the recommendations made in Cuijpers (Cuijpers, 2016). Statistical analysis was done using Comprehensive Meta-Analysis version 3 (Comprehensive Meta-Analysis Software (CMA), 2016). The effect size (Hedges’g) was calculated as the post-test difference between the mean of the treatment condition and the mean of the control condition, divided by the pooled post standard deviation and adjusted for sample size. For ease of clinical interpretation, we also calculated the NNT using both the effect sizes and Z scores (Kraemer & Kupfer, 2006). The NNT represents the number of patients one would expect to treat to have one more successful outcome. Where a study had multiple arms, each relevant arm was treated as a separate trial.

Effect sizes from each trial were pooled according to the random effects model, while differences between study subgroups were pooled according to the mixed effects model. As indicators of heterogeneity of pooled effect sizes, we calculated I2, which indicates the heterogeneity in percentages. We calculated 95% confidence intervals around I2 (Ionnidis, Patsopoulos, & Evangelou, 2016), using the non-central chi-squared-based approach within the heterogi module for Stata (Orsini, Bottai, Higgins, & Buchan, 2006). Publication bias was tested by inspecting the funnel plot on the primary outcome measures, and by a trim-and-fill procedure, which yields an estimate of the pooled effect size after accounting for bias (Duval & Tweedie, 2009).

3. Results

3.1. Study selection

A total of 4423 abstracts were examined from the following databases: PubMed (N = 1187), Cinahl (N = 139), PsychINFO (N = 538), Medline (N = 468), Social Sciences Citation Index (N = 1193) and Embase (N = 899). See Fig. 1, below.

Two of the 22 studies in the original meta-analysis contained multiple relevant arms, which were analysed as separate trials. 31 additional studies were identified following the full-text screen, making 53 randomised controlled studies in total. As studies with multiple relevant arms were treated as separate trials, a total of 64 efficacy trials were analysed. The control conditions varied from wait list in which treatment was deferred for a period (usually three months), to psychological placebos (information and discussion groups about the disorder in question; pseudo-active treatments) to care as usual in which the previous treatment was continued or changed, provided face to face or internet CBT was not introduced. The search also identified nine studies comparing face to face CBT with iCBT, three studies comparing iCBT to bibliotherapy and eight effectiveness studies of the benefits of iCBT when used in routine practice − these were used for separate analyses.

A systematic search of the literature looking for harms was conducted in February 2016, and yielded no results. Both qualitative and quantitative studies were sought, and no study design, date or language limits were imposed on the search. No studies specifically investigated the harms of iCBT. Furthermore, none of the studies examined in this meta-analysis made mention of harm or negative effects experienced by participants. It is the authors’ belief that even if the harms of ICBT were not the specific focus of a trial, had they occurred the study would have likely mentioned them. Nevertheless, we recognise that harm-specific research is lacking.

The Cochrane Collaboration tool for assessing risk of bias was used (Higgins et al., 2011). All studies used intention-to-treat methods. Studies with self-report methods precluded blinding, but controlled for investigator bias. 51 trials were judged to have a low risk of bias, while the remaining 13 were unclear. The uncertainty was predominantly due to a lack of information about allocation concealment.

Results of the meta-analysis of the 64 trials (Selmi, 1990; Andersson, 2005; Berger, Hämmerli, Gubser, Andersson, & Caspar, 2011; Choi et al., 2012; Christensen, 2004; de Graaf et al., 2009; Farrer, Christensen, Griffiths, & Mackinnon, 2011; Geraedts et al., 2014; Gilbody et al., 2015; Hallgren et al., 2015; Johansson et al., 2012; Kessler et al., 2009; Kivi et al., 2014; Lintvedt et al., 2011; Newby, Robins et al., 2016; O'Moore et al., 2018; Perini, Titov, & Andrews, 2009; Phillips et al., 2013; Richards et al., 2015; Rosso et al., 2017; Ruwaard et al., 2009; Smith et al., 2017; Titov et al., 2010; Vernmark et al., 2010; Warmerdam, van Straten, Twisk, Riper, & Cuijpers, 2008; Williams, Blackwell, Mackenzie, Holmes, & Andrews, 2013; Wright et al., 2005; Allen et al., 2016; Carlbring, Westling, Ljungstrand, Ekselius, & Andersson, 2001; Carlbring et al., 2006; Klein and Richards, 2001; Klein, Richards, & Austin, 2006; Oromendia, Orrego, Bonillo, & Molinuevo, 2016; Richards, Klein, & Austin, 2006; Ruwaard, Broeksteeg, Schrieken, Emmelkamp, & Lange, 2010; van Ballegooijen et al., 2013; Wims, Titov, Andrews, & Choi, 2010; Andersson et al., 2006; Andersson, Carlbring, & Furmark, 2012; Berger, Hohl, & Caspar, 2009; Botella et al., 2010; Carlbring et al., 2007; Furmark et al., 2009; Titov, Andrews, Schwencke, Drobny, & Einstein, 2008; Titov, Andrews, & Schwencke, 2008; Titov, Andrews, Choi, Schwencke, & Mahoney, 2008; Tulbure et al., 2015; Andersson, Paxling et al., 2012; Christensen et al., 2014a; Jones, Hadjistavropoulos, & Soucy, 2016; Paxling et al., 2011; Robinson et al., 2010; Titov et al., 2009) are displayed in Table 1: grouped by diagnosis, conditions studied, N randomised, outcome measure used, effect size of intervention compared to control condition (Hedges g), NNT, risk of bias, length of follow-up, adherence and patient satisfaction (as a proxy for acceptability). Summary data are in Table 2, Table 3, Table 4, Table 5 and a forest plot of the studies ranked by disorder shows the confidence limits around the effect sizes for each study (Fig. 2).

Table 1. Selected characteristics and results of randomised controlled studies examining the effects of cCBT and iCBT for adult depression and anxiety disorders.

Study	Conditions	N	Outcome Measure	Hedges’ g	NNT	Follow Up (Months)	Adherence (%)	Satisfaction (%)	Bias Risk
Major Depressive Disorder
Anderson (2005)	iCBT + support vs WLC + DG	75	BDI	0.90	2.10	6	65	–	Low
Berger (2011a)	iCBT vs WLC	51	BDI-II	0.72	2.56	6	36	–	Low
Berger (2011b)	iCBT + support vs WLC	51	BDI-II	1.09	1.79	6	56	–	Low
Choi (2012)	iCBT + support vs WLC	63	CBDI	1.51	1.4	3	68	96	Low
Christensen (2004)	CBT + support vs WLC + attention placebo	360	CES-D	0.34	5.26	12	66	–	Unclear
De Graaf (2009)	iCBT vs CAU	203	BDI-II	0.19	9.43	3, 6	–	–	Low
Farrer (2011a)	iCBT vs WLC	73	CES-D	0.57	3.18	–	16	–	Low
Farrer (2011b)	iCBT + support vs WLC	80	CES-D	0.83	2.26	6	18	–	Low
Geraedts (2014)	iCBT + support vs CAU	231	CES-D	0.24	7.46	6, 12	–	–	Low
Gilbody (2015a)	iCBT + support vs CAU	449	PHQ-9	0.02	83.3	12, 24	18	–	Low
Gilbody (2015b)	iCBT + support + CAU vs CAU	481	PHQ-9	0.12	14.71	12, 24	16	–	Low
Hallgren (2015)	iCBT + support vs CAU	629	MADRS	0.42	4.27	3	60	–	Low
Johansson (2012a)	Tailored iCBT + support vs WLC + DG	81	BDI-II	0.92	2.07	6	–	–	Unclear
Johansson (2012b)	Standardised iCBT + support vs WLC + DG	82	BDI-II	0.51	3.55	6	–	–	Unclear
Kessler (2009)	iCBT + CAU vs CAU	297	BDI	0.61	2.99	8	65	–	Low
Kivi (2004)	iCBT + support vs CAU	90	BDI-II	0.06	29.4	–	56	–	Unclear
Lintvedt (2013)	iCBT vs WLC	163	CES-D	0.67	2.75	–	–	83	Low
Newby (2016)	iCBT + support vs CAU	106	PHQ-9	1.08	1.81	3	66	85	Low
O’Moore (2016)	iCBT + support > CAU	69	PHQ-9	1.56	<1.4	3	84	95	Low
Perini (2009)	iCBT + support vs WLC	48	PHQ-9	0.73	2.54	–	74	82	Low
Phillips (2014)	iCBT + support vs CAU	637	PHQ-9	0.05	35.71	3	90	–	Low
Richards (2015)	iCBT + support vs WLC	262	BDI-II	0.75	2.48	3, 6	38	–	Low
Rosso (2016)	iCBT + support vs attention control	77	PHQ-9	0.89	2.13	–	92	–	Low
Ruwaard (2009)	iCBT + support vs WLC	54	BDI-IA	0.65	2.82	18	–	89	Unclear
Selmi (1990)	cCBT vs WLC	24	BDI	0.97	1.97	2	100	–	Unclear
Smith (2016)	iCBT + support vs WLC	270	PHQ-9	0.91	2.08	3	59	–	Low
Titov (2010a)	iCBT CA vs WLC	94	PHQ-9	1.43	1.45	4	70	87	Low
Titov (2010b)	iCBT TA vs WLC	92	PHQ-9	1.43	1.45	4	80	87	Low
Vernmark (2010)	iCBT + support vs WLC	88	BDI	0.65	2.82	6	59	–	Low
Warmerdan (2008)	iCBT + support vs WLC	263	CES-D	0.04	45.5	–	39	–	Low
Williams (2013)	iCBT + support vs WLC	69	BDI-II	1.05	1.85	–	56	84	Low
Wright (2005)	cCBT + support vs WLC	30	HAM-D	0.93	2.04	3, 6	91	–	Low

Panic Disorder/Agoraphobia
Allen (2016)	iCBT + support vs WLC	67	PDSS-SR	1.11	1.67	3	63	93	Low
Carlbring (2001)	iCBT + support vs WLC	41	BSQ	1.47	1.42	–	80	85	Low
Carlbring (2006)	iCBT + support vs WLC	60	BSQ	1.90	<1.4	9	80	97	Low
Klein (2001)	iCBT vs self-monitoring control	23	PDSS	0.39	4.59	–	90	–	Unclear
Klein (2006)	iCBT + support > IC	37	PDSS	3.07	<1.4	3	–	–	Low
Oromendia (2016a)	iCBT + non-scheduled support vs WLC	52	PDSS-SR	1.21	1.64	6	44	–	Low
Oromendia (2016b)	iCBT + scheduled support vs WLC	50	PDSS-SR	2.08	<1.4	6	68	–	Low
Richards (2006a)	iCBT + support vs IC	21	PDSS	1.28	1.58	3	–	–	Unclear
Richards (2006b)	iCBT + support + stress modules vs IC	20	PDSS	2.55	<1.4	3	–	–	Unclear
Ruwaard (2010	iCBT + support vs WLC	58	PDSS-SR	0.41	4.39	36	85	86	Unclear
Van Ballegooijen (2013)	iCBT + support vs WLC	126	PDSS-SR	0.28	6.41	–	6	–	Unclear
Wims (2010)	iCBT + support vs WLC	29	PDSS	0.76	2.44	1	79	–	Low

Social Anxiety Disorder
Andersson (2006)	iCBT + support vs WLC	64	LSAS-SR	0.83	2.26	12	56	–	Low
Andersson 2012_1	iCBT + support vs WLC	204	LSAS-SR	0.93	2.04	12	55	–	Low
Berger (2009)	iCBT + support vs WLC	52	LSAS-SR	0.61	2.99	–	57	85	Low
Botella (2010)	iCBT vs WLC	91	BFNE	0.45	4	12	48	–	Unclear
Carlbring (2007)	iCBT + support v WLC	57	SPS	1.01	1.91	12	93	–	Unclear
Furmark (2009)	iCBT + support vs WLC	80	SPS	0.82	2.28	12	63	70	Unclear
Titov (2008_1	iCBT + support vs WLC	105	SIAS	0.83	2.26	6	78	100	Low
Titov (2008_2)	iCBT + support vs WLC	88	SIAS	1.27	1.59	6	80	100	Low
Titov (2008_3a	iCBT + support vs WLC	67	SIAS	1.17	1.69	–	77	97	Low
Titov (2008_3b	iCBT vs WLC	66	SIAS	0.40	4.50	–	33	62	Low
Tulbure (2015)	iCBT + support vs WLC	76	LSAS-SR	1.28	1.58	6	39	86	Low

Generalised Anxiety Disorder
Andersson (2012_2)	iCBT + support vs WLC	54	PSWQ	0.17	10.4	3, 18	–	–	Low
Christensen (2014a)	iCBT vs WLC	222	GAD-7	0.07	25.0	6, 12	–	–	Low
Christensen (2014b)	iCBT + phone support vs WLC	221	GAD-7	0.46	3.91	6, 12	–	–	Low
Christensen (2014c)	iCBT + email support vs WLC	224	GAD-7	0.33	5.43	6, 12	–	–	Low
Jones (2016)	iCBT + support vs WLC	46	GAD-7	0.73	2.54	1	–	77	Low
Paxling (2011)	iCBT + support vs WLC	89	PSWQ	1.17	1.69	12, 36	11	–	Low
Robinson (2010a)	iCBT CA + support vs WLC	100	GAD-7	1.16	1.70	3	74	87	Low
Robinson (2010b)	iCBT TA + support vs WLC	99	GAD-7	1.05	1.85	3	80	87	Low
Titov (2009)	iCBT + support vs WLC	48	GAD-7	1.42	1.46	–	75	85	Low

Note: N: number randomised; g: Hedges g; NNT: number needed to treat; Bias risk (low, unclear, high (Ionnidis et al., 2016)); FU: follow up in months; Ad/Sat: percent randomised adhering to whole course/percent satisfied with course; - represents no data; iCBT: internet-delivered CBT; cCBT: computer-delivered CBT via CD-ROM; WLC: waitlist control; CAU: care as usual; CA: clinician-assisted; TA: technician-assisted; IC: information control; DG: discussion group; BDI: Beck Depression Inventory; BDI-II: Beck Depression Inventory II; BDI-IA: Beck Depression Inventory-IA; CBDI: Chinese Beck Depression Inventory; PHQ-9: Patient Health Questionnaire-9; CES-D: Centre for Epidemiologic Studies Depresson Scale ; MADRS: Montgomery-Asberg Depression Rating Scale ; HAM-D: Hamilton Depression Rating; PDSS-SR: Panic Disorder Severity Scale – Self-Rated; BSQ: Body Sensations Questionnaire; PDSS: Panic Disorder Severity Scale; LSAS-SR: Liebowitz Social Anxiety Scale – Self-Rated; SPS: Social Phobia Scale; SIAS: Social Interaction Anxiety Scale ; GAD-7: Generalised Anxiety Disorder-7; PSWQ: Penn State Worry Questionnaire.

Table 2. Summary results of subgroup analyses examining the effects of iCBT and cCBT for depression and anxiety disorders, the type of control group, risk of bias, and maintenance of improvement at follow-up.

	NTrials	NSubjects	g	95% CI (g)	p	I2	95% CI (I2)	NNT
All studies	64	8279	0.80	0.68–0.92	.00	84	81–87	2.34
MDD	32	5642	0.67	0.51–0.81	.00	84	79–99	2.78
PD	12	584	1.31	0.85–1.76	.00	84	74–90	1.55
SAD	11	950	0.92	0.76–1.08	.05	35	0–67	2.07
GAD	9	1103	0.70	0.39–1.01	.00	82	67–89	2.63

Note: NTrials: number of trials; NSubjects: number of subjects overall; g: Hedge’s g effect size of iCBT and cCBT over control conditions; 95% CI (g): 95% confidence interval for Hedge’s g results; p: significance of Hedge’s g results; I2: heterogeneity; 95% CI (I2): 95% confidence interval for I2; NNT: number needed to treat.

Table 3. Results of subgroup analysis examining the effects of iCBT and cCBT per the type of control group.

Control Condition	NTrials	NSubjects	g	95% CI (g)	p	I2	95% CI (I2)	NNT
CAU	10	3192	0.38	0.18–0.59	.00	86	78–91	4.60
WLC	50	5046	0.90	0.74–1.00	.00	74	66–80	2.10

Note: Control condition: control condition used; CAU: care as usual; WLC: waitlist control; NTrials: number of trials; NSubjects: number of subjects overall; g: Hedge’s g effect size of iCBT and cCBT over control condition; 95% CI (g): 95% confidence interval for Hedge’s g results; p: significance of Hedge’s g results; I2: heterogeneity; 95% CI (I2): 95% confidence interval for I2; NNT: number needed to treat.

Table 4. Results of subgroup analysis examining the effects of iCBT and cCBT according to the trial’s risk of bias.

Risk of Bias	NTrials	NSubjects	g	95% CI (g)	p	I2	95% CI (I2)	NNT
Low	50	7112	0.90	0.79–1.10	.00	86	84–89	2.10
Unclear	14	1167	0.74	0.39–0.74	.00	61	18–77	2.51

Note: Risk of bias: classified as per Cochrane Collaboration tool for assessing risk of bias [14]; NTrials: number of trials; NSubjects: number of subjects overall; g: Hedge’s g effect size of iCBT and cCBT over control condition; 95% CI (g): 95% confidence interval for Hedge’s g results; p: significance of Hedge’s g results; I2: heterogeneity; 95% CI (I2): 95% confidence interval for I2; NNT: number needed to treat.

Table 5. Results of subgroup analysis examining the effects of iCBT and cCBT at follow up, compared to immediately after trial completion.

Follow-Up	NTrials	NSubjects	g	95% CI (g)	p	I2	95% CI (I2)
3–6 months	29	4630	0.15	0.06–0.23	.05	32	0–56
9–18 months	15	2941	0.22	0.01–0.43	.00	75	51–86

Note: Follow-up: period of time (months) in which follow-up data was collected; NTrials: number of trials; NSubjects: number of subjects overall; g: Hedge’s g effect size of iCBT and cCBT at follow-up period, compared to immediately after trial completion; 95% CI (g): 95% confidence interval for Hedge’s g results; p: significance of Hedge’s g results; I2: heterogeneity; 95% CI (I2): 95% confidence interval for I2.

3.2. Between-group effect sizes

The overall effect size superiority of iCBT over control groups across all four disorders was 0.80 (95% CI 0.68–0.92). The combined Hedges’g for Major Depression was 0.67 (CI 0.51 − 0.81), for Panic Disorder 1.31 (CI 0.85–1.8), for Generalised Anxiety Disorder 0.70 (CI 0.39–1.0), and for Social Phobia 0.92 (CI 0.75–1.1). All means were above zero and heterogeneity (I2), as shown in Table 2, was substantial in most groups.

3.3. Subgroup analyses

3.3.1. Control group

As seen in Table 3 above, the mean effect size superiority over the control group for studies using a wait list control was higher (0.90) than for care as usual, (0.38, p < .05), indicating that the difference in improvement between iCBT and care as usual is less than with wait list controls (Watts, Turnell, Kladnitski, Newby, & Andrews, 2015).

3.3.2. Risk of bias

Risk of bias subgroup analyses were performed (see Table 4). The mean effect size superiority was higher for studies with a low risk of bias (0.90) than those where the risk of bias was deemed unclear (0.74, p < .05).

3.3.3. Maintenance of improvement

A majority of trials (51/64) reported follow-up data that ranged from 1 to 36 months post-treatment (median 6 months). Our analysis of the effect size superiority of iCBT over control at follow-up, versus post-treatment, was conducted for two groups (44 trials) – 3–6 months, and 9–18 months (Table 5) with significantly increased benefit at both periods.

3.3.4. Satisfaction and adherence

Adherence and satisfaction are indicators of acceptability of iCBT to patients and 52/64 trials measured one or both. Median adherence was 66% (50/64 trials) and the interquartile range was 29% (Q1 52%, Q3 80%). 24/64 trials provided data on patient satisfaction, with a median of 86% (range 62–100%) of patients reporting that they were satisfied or very satisfied.

3.3.5. Face to face CBT vs iCBT

Nine studies compared computerised CBT to face-to-face therapy (Selmi, 1990; Wright et al., 2005; Botella et al., 2010; Wagner, Horn, & Maercker, 2014; Andersson et al., 2013; Kiropoulos et al., 2008; Carlbring et al., 2005; Andrews, Davies, & Titov, 2011; Bergström et al., 2010), four in MDD, three in PD and two in SP. There were 568 subjects in total, 301 in the iCBT condition and 267 in the face-to-face group. The effect size indicating the difference between iCBT and face-to-face treatments was not significant, g = 0.14 in favour of face-to-face CBT (95% CI: −0.04–0.32).

Five of eight studies reported therapist time (Andersson et al., 2013; Kiropoulos et al., 2008; Carlbring et al., 2005; Andrews et al., 2011; Bergström et al., 2010); on average, therapists spent 7.8 times (SD 4.5) the amount of time on face-to-face subjects than on iCBT participants. The time spent per patient is shown in Table 6, below.

Table 6. Therapist time spent per patient in either iCBT or face-to-face CBT, and between-group effect size significance for primary outcome measure.

Study	Time (iCBT)	SD (iCBT)	Time (F-F)	SD (F-F)	p (Hedge’s g)
Andersson et al. (2013)	36	15	290	265	<.05, favouring F-F
Kiropoulos et al. (2008)	352	240	268	255	>.05
Carlbring et al. (2005)	150	–	450–600	–	>.05
Andrews et al. (2011)	18	–	240	–	>.05
Bergström et al., 2010	35	19	360	–	>.05

Note: Time (iCBT): therapist time spent in iCBT condition, in minutes; SD (iCBT): standard deviation of iCBT therapist time, in minutes; Time (F-F): therapist time spent in face to face condition, in minutes; SD (F-F): standard deviation of fact to face therapist time, in minutes; p (Hedge’s g): significance of difference in Hedge’s g effect size between iCBT condition and face to face condition.

3.3.6. Bibliotherapy CBT vs iCBT

Three studies compared iCBT with bibliotherapy (Smith et al., 2017; Klein et al., 2006; Furmark et al., 2009), one each for MDD, PD and SP, with 255 participants in total – 120 in iCBT and 135 in bibliotherapy. All three had control arms, so were included in the meta-analysis. There was no significant difference overall, with g = 0.12 favouring iCBT (CI −0.12–0.36).

3.3.7. Effectiveness

Eight papers found in the original literature search investigated the effectiveness of iCBT in routine clinical practice (Watts et al., 2015; El Alaoui et al., 2015a; El Alaoui et al., 2015b; Hedman et al., 2014; Hedman et al., 2013; Mewton, Wong, & Andrews, 2012; Ruwaard et al., 2012; Williams and Andrews, 2013). All four disorders were represented in the studies, and the results were congruent with those of efficacy trials, with a pre-post effect size of g = 1.07. Three studies reported the therapist time spent – 11, 11.5 and 12 min per patient per week.

4. Discussion

The results of this study were similar to those of the original meta-analysis. Overall, the mean effect size superiority of iCBT over the control group was 0.88 in the original 22 studies and 0.80 in these 64 studies, with a corresponding rise in NNT from 2.15 to 2.34. Maintenance of improvement at follow-up was demonstrated with small, but significant, effect size superiority at both 3–6 and 9–18 month follow-up. The results are indicative of both short and long term benefit. Efficacy studies suffer from the risk that participants could be unlike patients in routine practice. Computerised treatment automatically generates progress data and this makes studies of effectiveness in routine practice possible. While adherence in practice is lower than in the research trials, the benefits to completers are comparable to those seen in RCTs of the same course, in panic (Carlbring et al., 2001), generalised anxiety disorder (Mewton et al., 2012) depression (Christensen et al., 2014b), or social anxiety disorder (Williams, O'Moore, Mason, & Andrews, 2014), providing further support for the results in the efficacy trials.

The control group was usually a delayed treatment group in which there was no expectation that the delay before treatment would be beneficial. None involved a pill placebo. Nevertheless, the control group did improve – presumably a function of regression to the mean and the natural history of the disorders during the time on the wait list.

Participants showed high rates of satisfaction though only one third of studies measured this. There were acceptable levels of adherence to iCBT. At 6%–100%, the range was large, but only 10/50 trials reported adherence rates below 50%. Adherence in the iCBT and bibliotherapy conditions were comparable, and there was no significant difference between the iCBT and face to face CBT conditions. Although the data was sparse, it appears as though the therapist time required for face to face therapy was, as expected, significantly greater than for iCBT. There is a need for further research in this area, to establish the minimum amount of therapist time required for maximal benefit. This evidence supports the original claim that iCBT is efficacious and acceptable, and provides increased access to treatment for people suffering from anxiety and depression (Andrews et al., 2010).

Control group subgroup analyses showed that iCBT was more effective against waitlist control, versus care as usual. Care as usual has a more significant benefit than being on a waitlist for treatment (Williams & Andrews, 2013).

Risk of bias subgroup analyses showed that the effect size for studies with low bias was higher than those with unclear bias, although the effect size was still large in those with unclear bias.

5. Limitations

Studies variably measured changes in quality of life and disability (for e.g. reduction in work loss days (Mackenzie, Harvey, Mewton, & Andrews, 2014)) with improvement consistent with reduction in primary symptomatology. No systematic analyses of these data were performed.

The mean effect size, indicating the superiority of iCBT over the control group, was 0.80, NNT 2.34. The most common control group was waitlist, with a minority including CAU, informational controls or attention controls. There were no studies comparing iCBT with pill placebo, or iCBT with pharmacotherapy. The original meta-analysis mentioned that iCBT compared to waitlist control resulted in higher effect sizes than when compared to treatment as usual. This finding was confirmed by our results, in which the effect size for studies compared to CAU was 0.38, versus 0.90 against a waitlist control. The lack of comparisons with medication is a serious weakness of the field, for many clinicians will not see iCBT as a bona fide treatment until such comparisons are available. There are three difficulties in doing such research. First, it is not in the interests of pharmaceutical companies to fund or to supply medication for such research. Second, people recruited for a drug trial have to be able to attend the investigators whereas applicants for iCBT trials can live far away, and third, applicants for iCBT trials appear to have a strong aversion to being randomised to medication (Christensen et al., 2014b).

There is evidence, as explained above, that there was no significant difference between iCBT and bibliotherapy in three studies. If the bibliotherapy used is of a high standard this is unsurprising, given the same material is learned − be it from a screen or from a book − it should affect the disorder in a similar manner.

The iCBT courses were diverse. The content varied according to diagnosis (transdiagnostic courses are the topic of a separate meta-analysis (Newby, Twomey et al., 2016)), but even within a diagnosis, the range of CBT topics differed. The form in which the information was presented also varied markedly, i.e. in the use of text, audio, video, cartoon story lines and in the emphasis on field assignments and the use of other supplementary material. The topic has grown to the point where individual iCBT courses should perhaps be treated differently, exactly as different SSRIs are analysed separately. For instance, there are eight trials of the ThisWayUp course for depression in this meta-analysis (mean between group ES = 1.21) (Choi et al., 2012; O'Moore et al., 2018; Perini et al., 2009; Rosso et al., 2017; Smith et al., 2017; Titov et al., 2010; Williams et al., 2013) and four trials of the Andersson depression course (Andersson, 2005; Johansson et al., 2012; Vernmark et al., 2010) (mean between group ES = 0.75). Differences between courses could be of interest.

The Agency for Healthcare Research and Quality have issued a clinician advisory that in depression, the benefits of CBT and Medication are comparable (Agency for Healthcare Research and Quality, 2016). In other studies medications show a small superiority over CBT (0.34 for MDD 11 studies (Cuijpers & Cristea, 2015), 0.45 for anxiety disorders, 7 studies (Bandelow et al., 2015)). As there are serious side effects with medication, most clinical practice guidelines for anxiety and depressive disorders recommend use of CBT as the first line of treatment. In clinical practice, the number of prescriptions for medication exceed those for CBT because medication is easy to prescribe, relatively cheap, the quality is guaranteed and it is widely available − whereas a referral for face to face CBT means finding a therapist with vacancies, who costs no more than medication, and whose practice is quality assured. iCBT is different − it is easy to prescribe, costs the same as two months of medication, the quality is guaranteed and it is available wherever there is internet or phone access. We therefore contend that iCBT should the treatment of first choice anxiety or depression, used alone, or in combination with medication, as preferred by the patient.

In conclusion, the 64 identified iCBT trials generated large effect size superiority over control groups, with maintenance of benefit at follow-up, acceptable patient adherence and high rates of satisfaction and now with evidence of effectiveness in routine practice.

References

Agency for Healthcare Research and Quality, 2016: Agency for Healthcare Research and Quality
Nonpharmacological versus pharmacological treatment for patients with major depressive disorder: Current state of the evidence
AHRQ Clinician Summary, 15 (16) (2016)
Google Scholar
Allen et al., 2016: A. Allen, J. Newby, A. Mackenzie, J. Smith, M. Boulton, S. Loughnan, et al.
Internet cognitive–behavioral treatment for panic disorder: Randomised controlled trial and evidence of effectiveness in primary care
British Journal of Psychiatry Open, 2 (2) (2016), pp. 154-162
View PDF
CrossRef View Record in Scopus Google Scholar
Andersson et al., 2006: G. Andersson, P. Carlbring, A. Holmström, E. Sparthan, T. Furmark, E. Nilsson-Ihrfelt, et al.
Internet-based self-help with therapist feedback and in vivo group exposure for social phobia: A randomized controlled trial
Journal of Consulting and Clinical Psychology, 74 (4) (2006), pp. 677-686
View Record in Scopus Google Scholar
Andersson et al., 2013: G. Andersson, H. Hesser, A. Veilord, L. Svedling, F. Andersson, O. Sleman, et al.
Randomised controlled non-inferiority trial with 3-year follow-up of internet-delivered versus face-to-face group cognitive behavioral therapy for depression
Journal of Affective Disorders [Internet], 151 (3) (2013), pp. 986-994, 10.1016/j.jad.2013.08.022
[cited 8 September 2016] Available from:
Article Download PDF View Record in Scopus Google Scholar
Andersson et al., 2014: G. Andersson, P. Cuijpers, P. Carlbring, H. Riper, E. Hedman
Guided Internet-based vs. face-to-face cognitive behavior therapy for psychiatric and somatic disorders: A systematic review and meta-analysis
World Psychiatry, 13 (3) (2014), pp. 288-295
View PDF
CrossRef View Record in Scopus Google Scholar
Andersson, 2005: G. Andersson
Internet-based self-help for depression: Randomised controlled trial
The British Journal of Psychiatry, 187 (5) (2005), pp. 456-461
View PDF
CrossRef View Record in Scopus Google Scholar
Andersson, Carlbring et al., 2012: G. Andersson, P. Carlbring, T. Furmark
Therapist experience and knowledge acquisition in internet-delivered CBT for social anxiety disorder: A randomized controlled trial
Public Library Of Science, 7 (5) (2012), p. e37411
View PDF
CrossRef View Record in Scopus Google Scholar
Andersson, Paxling et al., 2012: G. Andersson, B. Paxling, P. Roch-Norlund, G. Östman, A. Norgren, J. Almlöv, et al.
Internet-Based psychodynamic versus cognitive behavioral guided self-help for generalized anxiety disorder: A randomized controlled trial
Psychotherapy and Psychosomatics, 81 (6) (2012), pp. 344-355
View PDF
CrossRef View Record in Scopus Google Scholar
Andrews et al., 2010: G. Andrews, P. Cuijpers, M. Craske, P. McEvoy, N. Titov
Computer therapy for the anxiety and depressive disorders is effective, acceptable and practical health care: A meta-analysis
Public Library Of Science, 5 (10) (2010), p. e13196
View PDF
CrossRef View Record in Scopus Google Scholar
Andrews et al., 2011: G. Andrews, M. Davies, N. Titov
Effectiveness randomized controlled trial of face to face versus Internet cognitive behaviour therapy for social phobia
Australian & New Zealand Journal of Psychiatry, 45 (4) (2011), pp. 337-340
View PDF
CrossRef View Record in Scopus Google Scholar
Bandelow et al., 2015: B. Bandelow, M. Reitt, C. Rover, S. Michaelis, Y. Gorlich, D. Wedekind
Efficacy of treatments for anxiety disorders: A meta-analysis
International Clinical Psychopharmacology, 30 (2015), pp. 183-192
View Record in Scopus Google Scholar
Berger et al., 2009: T. Berger, E. Hohl, F. Caspar
Internet-based treatment for social phobia: A randomized controlled trial
Journal of Clinical Psychology, 65 (10) (2009), pp. 1021-1035
View PDF
CrossRef View Record in Scopus Google Scholar
Berger et al., 2011: T. Berger, K. Hämmerli, N. Gubser, G. Andersson, F. Caspar
Internet-based treatment of depression: A randomized controlled trial comparing guided with unguided self-help
Cognitive Behaviour Therapy, 40 (4) (2011), pp. 251-266
View PDF
CrossRef View Record in Scopus Google Scholar
Bergström et al., 2010: J. Bergström, G. Andersson, B. Ljótsson, C. Rück, S. Andréewitch, A. Karlsson, et al.
Internet-versus group-administered cognitive behaviour therapy for panic disorder in a psychiatric setting: A randomised trial
BioMed Central Psychiatry, 10 (1) (2010)
Google Scholar
Botella et al., 2010: C. Botella, M. Gallego, A. Garcia-Palacios, V. Guillen, R. Baños, S. Quero, et al.
An internet-based self-help treatment for fear of public speaking: A controlled trial
Cyberpsychology, Behavior, and Social Networking, 13 (4) (2010), pp. 407-421
View PDF
CrossRef View Record in Scopus Google Scholar
Carlbring et al., 2001: P. Carlbring, B. Westling, P. Ljungstrand, L. Ekselius, G. Andersson
Treatment of panic disorder via the internet: A randomized trial of a self-help program
Behavior Therapy, 32 (4) (2001), pp. 751-764
Article Download PDF View Record in Scopus Google Scholar
Carlbring et al., 2005: P. Carlbring, E. Nilsson-Ihrfelt, J. Waara, C. Kollenstam, M. Buhrman, V. Kaldo, et al.
Treatment of panic disorder: Live therapy vs. self-help via the internet
Behaviour Research and Therapy, 43 (10) (2005), pp. 1321-1333
Article Download PDF View Record in Scopus Google Scholar
Carlbring et al., 2006: P. Carlbring, S. Bohman, S. Brunt, M. Buhrman, B. Westling, L. Ekselius, et al.
Remote treatment of panic disorder: A randomized trial of internet-based cognitive behavior therapy supplemented with telephone calls
American Journal of Psychiatry, 163 (12) (2006), pp. 2119-2125
View Record in Scopus Google Scholar
Carlbring et al., 2007: P. Carlbring, M. Gunnarsdottir, L. Hedensjo, G. Andersson, L. Ekselius, T. Furmark
Treatment of social phobia: Randomised trial of internet-delivered cognitive-behavioral therapy with telephone support
The British Journal of Psychiatry, 190 (2) (2007), pp. 123-128
View PDF
CrossRef View Record in Scopus Google Scholar
Choi et al., 2012: I. Choi, J. Zou, N. Titov, B. Dear, S. Li, L. Johnston, et al.
Culturally attuned Internet treatment for depression amongst Chinese Australians: A randomised controlled trial
Journal of Affective Disorders, 136 (3) (2012), pp. 459-468
Article Download PDF View Record in Scopus Google Scholar
Christensen et al., 2014a: H. Christensen, A. Mackinnon, P. Batterham, B. O'Dea, A. Guastella, K. Griffiths, et al.
The effectiveness of an online e-health application compared to attention placebo or Sertraline in the treatment of Generalised Anxiety Disorder
Internet Interventions, 1 (4) (2014), pp. 169-174
Article Download PDF View Record in Scopus Google Scholar
Christensen et al., 2014b: H. Christensen, A. Mackinnon, P. Batterham, B. O’Dea, A. Guastella, K. Griffiths, et al.
The effectiveness of an online e-health application compared to attention placebo or Setraline in the treatment of Generalised Anxiety Disorder
Internet Interventions, 16 (2014), pp. 9-174
View Record in Scopus Google Scholar
Christensen, 2004: H. Christensen
Delivering interventions for depression by using the internet: Randomised controlled trial
British Medical Journal, 328 (7434) (2004), p. 265
View PDF
View Record in Scopus Google Scholar
Comprehensive Meta-Analysis Software (CMA), 2016: Comprehensive Meta-Analysis Software (CMA)
Meta-analysis.com
(2016)
[Internet]. [cited 8 September 2016]. Available from:
https://www.meta-analysis.com/
Google Scholar
Cuijpers and Cristea, 2015: P. Cuijpers, I. Cristea
What if a placebo effect explained all the activity of depression treatments?
World Psychiatry, 14 (3) (2015), pp. 310-311
View PDF
CrossRef View Record in Scopus Google Scholar
Cuijpers, 2016: P. Cuijpers
Meta-analyses in mental health research: A practical guide
Vrije Universitieit Amsterdam, Amsterdam (2016)
Google Scholar
de Graaf et al., 2009: L. de Graaf, S. Gerhards, A. Arntz, H. Riper, J. Metsemakers, S. Evers, et al.
Clinical effectiveness of online computerised cognitive-behavioral therapy without support for depression in primary care: Randomised trial
The British Journal of Psychiatry, 195 (1) (2009), pp. 73-80
View PDF
CrossRef View Record in Scopus Google Scholar
Duval and Tweedie, 2009: S. Duval, R. Tweedie
A nonparametric trim and fill method of accounting for publication bias in meta-analysis
Journal of the American Statistical Association, 1 (104) (2009), pp. 1338-1350
Google Scholar
El Alaoui et al., 2015a: S. El Alaoui, et al.
Effectiveness of internet-based cognitive-behavior therapy for social anxiety disorder in clinical psychiatry
Journal of Consulting and Clinical Psychology, 83 (5) (2015), pp. 902-914
[Web]
View PDF
CrossRef View Record in Scopus Google Scholar
El Alaoui et al., 2015b: S. El Alaoui, et al.
Long-term effectiveness and outcome predictors of therapist-guided internet-based Cognitive-behavioral therapy for social anxiety disorder In routine psychiatric care
British Medical Journal Open, 5 (6) (2015), p. e007902
[Web]
View PDF
CrossRef View Record in Scopus Google Scholar
Farrer et al., 2011: L. Farrer, H. Christensen, K. Griffiths, A. Mackinnon
Internet-based CBT for depression with and without telephone tracking in a national helpline: Randomised controlled trial
Public Library Of Science, 6 (11) (2011), p. e28099
View PDF
CrossRef View Record in Scopus Google Scholar
Furmark et al., 2009: T. Furmark, P. Carlbring, E. Hedman, A. Sonnenstein, P. Clevberger, B. Bohman, et al.
Guided and unguided self-help for social anxiety disorder: Randomised controlled trial
The British Journal of Psychiatry, 195 (5) (2009), pp. 440-447
View PDF
CrossRef View Record in Scopus Google Scholar
Geraedts et al., 2014: A. Geraedts, A. Kleiboer, J. Twisk, N. Wiezer, W. van Mechelen, P. Cuijpers
Long-term results of a web-based guided self-help intervention for employees with depressive symptoms: Randomized controlled trial
Journal of Medical Internet Research, 16 (7) (2014), p. e168
View PDF
CrossRef Google Scholar
Gilbody et al., 2015: S. Gilbody, E. Littlewood, C. Hewitt, G. Brierley, P. Tharmanathan, R. Araya, et al.
Computerised cognitive behaviour therapy (cCBT) as treatment for depression in primary care (REEACT trial): Large scale pragmatic randomised controlled trial
British Medical Journal (2015), p. h5627
View PDF
CrossRef View Record in Scopus Google Scholar
Hallgren et al., 2015: M. Hallgren, M. Kraepelien, A. Ojehagen, N. Lindefors, Z. Zeebari, V. Kaldo, et al.
Physical exercise and internet-based cognitive-behavioral therapy in the treatment of depression: Randomised controlled trial
The British Journal of Psychiatry, 207 (3) (2015), pp. 227-234
View PDF
CrossRef View Record in Scopus Google Scholar
Hedges and Vevea, 1996: L. Hedges, J. Vevea
Estimating effect size under publication bias: Small sample properties and robustness of a random effects selection model
Journal of Educational and Behavioral Statistics, 21 (4) (1996), pp. 299-332
View Record in Scopus Google Scholar
Hedman et al., 2012: E. Hedman, B. Ljotsson, N. Lindefors
Cognitive behavior therapy via the Internet: A systematic review of applications, clinical efficacy and cost-effectiveness
Expert Review of Pharmacoeconomics and Outcomes Research, 12 (6) (2012), pp. 745-764
View PDF
CrossRef View Record in Scopus Google Scholar
Hedman et al., 2013: E. Hedman, et al.
Effectiveness of internet-based cognitive behaviour therapy for panic disorder in routine psychiatric care
Acta Psychiatrica Scandinavica, 128 (6) (2013), pp. 457-467
View PDF
CrossRef View Record in Scopus Google Scholar
Hedman et al., 2014: E. Hedman, et al.
Effectiveness of internet-based cognitive behaviour therapy for depression in routine psychiatric care
Journal of Affective Disorders, 155 (2014), pp. 49-58
[Web]
Article Download PDF View Record in Scopus Google Scholar
Higgins et al., 2011: J. Higgins, D. Altman, P. Gotzsche, P. Juni, D. Moher, A. Oxman, et al.
The Cochrane Collaboration's tool for assessing risk of bias in randomised trials
British Medical Journal, 343 (October (2)) (2011), p. d5928
View PDF
CrossRef View Record in Scopus Google Scholar
Ionnidis et al., 2016: J. Ionnidis, N. Patsopoulos, E. Evangelou
Uncertainty in heterogeneity estimates in meta-analyses
British Medical Journal (Clinical Research Ed.), 335 (7626) (2016), pp. 914-916
Google Scholar
Johansson et al., 2012: R. Johansson, E. Sjöberg, M. Sjögren, E. Johnsson, P. Carlbring, T. Andersson, et al.
Tailored vs. standardized internet-based cognitive behavior therapy for depression and comorbid symptoms: A randomized controlled trial
Public Library Of Science, 7 (5) (2012), p. e36905
View PDF
CrossRef View Record in Scopus Google Scholar
Jones et al., 2016: S. Jones, H. Hadjistavropoulos, J. Soucy
A randomized controlled trial of guided internet-delivered cognitive behaviour therapy for older adults with generalized anxiety
Journal of Anxiety Disorders, 37 (2016), pp. 1-9
Article Download PDF CrossRef View Record in Scopus Google Scholar
Kessler et al., 2009: D. Kessler, G. Lewis, S. Kaur, N. Wiles, M. King, S. Weich, et al.
Therapist-delivered internet psychotherapy for depression in primary care: A randomised controlled trial
The Lancet, 374 (9690) (2009), pp. 628-634
Article Download PDF View Record in Scopus Google Scholar
Kiropoulos et al., 2008: L. Kiropoulos, B. Klein, D. Austin, K. Gilson, C. Pier, J. Mitchell, et al.
Is internet-based CBT for panic disorder and agoraphobia as effective as face-to-face CBT?
Journal of Anxiety Disorders, 22 (8) (2008), pp. 1273-1284
Article Download PDF View Record in Scopus Google Scholar
Kivi et al., 2014: M. Kivi, M. Eriksson, D. Hange, E. Petersson, K. Vernmark, B. Johansson, et al.
Internet-based therapy for mild to moderate depression in swedish primary care: Short term results from the PRIM-NET randomized controlled trial
Cognitive Behaviour Therapy, 43 (4) (2014), pp. 289-298
View PDF
CrossRef View Record in Scopus Google Scholar
Klein and Richards, 2001: B. Klein, J. Richards
A brief internet-based treatment for panic disorder
Behavioral and Cognitive Psychotherapy, 29 (01) (2001)
Google Scholar
Klein et al., 2006: B. Klein, J. Richards, D. Austin
Efficacy of internet therapy for panic disorder
Journal of Behavior Therapy and Experimental Psychiatry, 37 (3) (2006), pp. 213-238
Article Download PDF View Record in Scopus Google Scholar
Kraemer and Kupfer, 2006: H. Kraemer, D. Kupfer
Size of treatment effects and their importance to clinical research and practice
Biological Psychiatry, 59 (11) (2006), pp. 990-996
Article Download PDF View Record in Scopus Google Scholar
Lintvedt et al., 2011: O. Lintvedt, K. Griffiths, K. Sørensen, A. Østvik, C. Wang, M. Eisemann, et al.
Evaluating the effectiveness and efficacy of unguided internet-based self-help intervention for the prevention of depression: A randomized controlled trial
Clinical Psychology & Psychotherapy, 20 (1) (2011), pp. 10-27
Google Scholar
Mackenzie et al., 2014: A. Mackenzie, S. Harvey, L. Mewton, G. Andrews
Occupational impact of internet-delivered cognitive behaviour therapy for depression and anxiety: Reanalysis of data from five Australian randomised controlled trials
The Medical Journal of Australia, 201 (7) (2014), pp. 417-419
View PDF
CrossRef View Record in Scopus Google Scholar
Mewton et al., 2012: L. Mewton, N. Wong, G. Andrews
The effectiveness of internet cognitive behavioral therapy for generalised anxiety disorder in clinical practice
Depression and Anxiety, 29 (10) (2012), pp. 843-849
View PDF
CrossRef View Record in Scopus Google Scholar
Moher et al., 2009: D. Moher, A. Liberati, J. Tetzlaff, D. Altman
Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement
British Medical Journal, 339 (July (1)) (2009), p. b2535
View PDF
CrossRef View Record in Scopus Google Scholar
Newby, Robins et al., 2016: J. Newby, L. Robins, K. Wilhelm, J. Smith, T. Fletcher, I. Gillis, et al.
Internet-delivered cognitive behaviour therapy for depression in people with diabetes mellitus: A randomised controlled trial
Journal of Medical Internet Research, 19 (5) (2016)
Google Scholar
Newby, Twomey et al., 2016: J. Newby, C. Twomey, S. Yuan Li, G. Andrews
Transdiagnostic computerised cognitive behavioral therapy for depression and anxiety: A systematic review and meta-analysis
Journal of Affective Disorders, 199 (2016), pp. 30-41
Article Download PDF View Record in Scopus Google Scholar
O'Moore et al., 2018: K. O'Moore, J. Newby, G. Andrews, D. Hunter, K. Bennell, J. Smith, et al.
The effect of internet cognitive behaviour therapy for depression in older adults with knee osteoarthritis: A randomized controlled trial
Arthritis Care and Research, 70 (2018), pp. 61-70
View PDF
CrossRef View Record in Scopus Google Scholar
Olthius et al., 2015: J.V. Olthius, M.C. Watt, K. Bailey, J.A. Hayden, S.H. Stewart
Therapist-supported Internet cognitive behavioural therapy for anxiety in adults
Cochrane Database of Systematic Reviews (2015), p. 3
View Record in Scopus Google Scholar
Oromendia et al., 2016: P. Oromendia, J. Orrego, A. Bonillo, B. Molinuevo
Internet-based self-help treatment for panic disorder: A randomized controlled trial comparing mandatory versus optional complementary psychological support
Cognitive Behaviour Therapy, 45 (4) (2016), pp. 270-286
View PDF
CrossRef View Record in Scopus Google Scholar
Orsini et al., 2006: N. Orsini, M. Bottai, J. Higgins, I. Buchan
HETEROGI. Stata module to quantify heterogeneity in a meta-analysis
(2006)
[Stata]
Google Scholar
Paxling et al., 2011: B. Paxling, J. Almlöv, M. Dahlin, P. Carlbring, E. Breitholtz, T. Eriksson, et al.
Guided internet-delivered cognitive behavior therapy for generalized anxiety disorder: A randomized controlled trial
Cognitive Behaviour Therapy, 40 (3) (2011), pp. 159-173
View PDF
CrossRef View Record in Scopus Google Scholar
Perini et al., 2009: S. Perini, N. Titov, G. Andrews
Clinician-assisted Internet-based treatment is effective for depression: Randomized controlled trial
Australian & New Zealand Journal of Psychiatry, 43 (6) (2009), pp. 571-578
View PDF
CrossRef View Record in Scopus Google Scholar
Phillips et al., 2013: R. Phillips, J. Schneider, I. Molosankwe, M. Leese, P. Foroushani, P. Grime, et al.
Randomized controlled trial of computerized cognitive behavioral therapy for depressive symptoms: Effectiveness and costs of a workplace intervention
Psychological Medicine, 44 (04) (2013), pp. 741-752
Google Scholar
Richards et al., 2006: J. Richards, B. Klein, D. Austin
Internet cognitive behavioral therapy for panic disorder: Does the inclusion of stress management information improve end-state functioning?
Clinical Psychologist, 10 (1) (2006), pp. 2-15
View PDF
CrossRef View Record in Scopus Google Scholar
Richards et al., 2015: D. Richards, L. Timulak, E. O'Brien, C. Hayes, N. Vigano, J. Sharry, et al.
A randomized controlled trial of an internet-delivered treatment: Its potential as a low-intensity community intervention for adults with symptoms of depression
Behaviour Research and Therapy, 75 (2015), pp. 20-31
Article Download PDF View Record in Scopus Google Scholar
Robinson et al., 2010: E. Robinson, N. Titov, G. Andrews, K. McIntyre, G. Schwencke, K. Solley
Internet treatment for generalized anxiety disorder: A randomized controlled trial comparing clinician vs technician assistance
Public Library Of Science, 5 (6) (2010), p. e10942
View PDF
CrossRef View Record in Scopus Google Scholar
Rosso et al., 2017: I. Rosso, W. Killgore, E. Olson, C. Webb, R. Fukunaga, R. Auerbach, et al.
Randomized trial of internet-based cognitive behavior therapy for major depressive disorder
Depression and Anxiety, 34 (3) (2017), pp. 236-245
View PDF
CrossRef View Record in Scopus Google Scholar
Ruwaard et al., 2009: J. Ruwaard, B. Schrieken, M. Schrijver, J. Broeksteeg, J. Dekker, H. Vermeulen, et al.
Standardized web-based cognitive behavioral therapy of mild to moderate depression: A randomized controlled trial with a long-term follow-up
Cognitive Behaviour Therapy, 38 (4) (2009), pp. 206-221
View PDF
CrossRef View Record in Scopus Google Scholar
Ruwaard et al., 2010: J. Ruwaard, J. Broeksteeg, B. Schrieken, P. Emmelkamp, A. Lange
Web-based therapist-assisted cognitive behavioral treatment of panic symptoms: A randomized controlled trial with a three-year follow-up
Journal of Anxiety Disorders, 24 (4) (2010), pp. 387-396
Article Download PDF View Record in Scopus Google Scholar
Ruwaard et al., 2012: J. Ruwaard, et al.
The effectiveness of online cognitive behavioral treatment in routine clinical practice
Public Library Of Science, 7 (7) (2012), p. e40089
[Web]
View PDF
CrossRef View Record in Scopus Google Scholar
Selmi, 1990: P. Selmi
Computer-administered cognitive-behavioral therapy for depression
American Journal of Psychiatry, 147 (1) (1990), pp. 51-56
View Record in Scopus Google Scholar
Shafran et al., 2009: R. Shafran, D. Clark, C. Fairburn, A. Arntz, D. Barlow, A. Ehlers, et al.
Mind the gap: Improving the dissemination of CBT
Behaviour Research and Therapy, 47 (11) (2009), pp. 902-909
Article Download PDF View Record in Scopus Google Scholar
Sijbrandij et al., 2016: M. Sijbrandij, I. Kunovski, P. Cuijpers
Effectiveness of internet-delivered cognitive behavioral therapy for posttraumatic stress disorder: A systematic review and meta-analysis
Depression and Anxiety, 33 (2016), pp. 783-791
View PDF
CrossRef View Record in Scopus Google Scholar
Smith et al., 2017: J. Smith, J. Newby, N. Burston, M. Murphy, S. Michael, F. Kiln, et al.
Help from home for depression: A randomised controlled trial comparing internet cognitive behaviour therapy for depression with two self-help books
Internet Interventions, 9 (2017), pp. 25-37
Article Download PDF View Record in Scopus Google Scholar
Titov et al., 2009: N. Titov, G. Andrews, E. Robinson, G. Schwencke, L. Johnston, K. Solley, et al.
Clinician-assisted Internet-based treatment is effective for generalized anxiety disorder: Randomized controlled trial
Australian & New Zealand Journal of Psychiatry, 43 (10) (2009), pp. 905-912
View PDF
CrossRef View Record in Scopus Google Scholar
Titov et al., 2010: N. Titov, G. Andrews, M. Davies, K. McIntyre, E. Robinson, K. Solley
Internet treatment for depression: A randomized controlled trial comparing clinician vs technician assistance
Public Library Of Science, 5 (6) (2010), p. e10939
View PDF
CrossRef View Record in Scopus Google Scholar
Titov, Andrews and Schwencke, 2008: N. Titov, G. Andrews, G. Schwencke
Shyness 2: Treating social phobia online: Replication and extension
Australian & New Zealand Journal of Psychiatry, 42 (7) (2008), pp. 595-605
View PDF
CrossRef View Record in Scopus Google Scholar
Titov, Andrews, Choi et al., 2008: N. Titov, G. Andrews, I. Choi, G. Schwencke, A. Mahoney
Shyness 3: Randomized controlled trial of guided versus unguided Internet-based CBT for social phobia
Australian & New Zealand Journal of Psychiatry, 42 (12) (2008), pp. 1030-1040
View PDF
CrossRef View Record in Scopus Google Scholar
Titov, Andrews, Schwencke, Drobny et al., 2008: N. Titov, G. Andrews, G. Schwencke, J. Drobny, D. Einstein
Shyness 1: Distance treatment of social phobia over the Internet
Australian & New Zealand Journal of Psychiatry, 42 (7) (2008), pp. 585-594
View PDF
CrossRef View Record in Scopus Google Scholar
Tulbure et al., 2015: B. Tulbure, A. Szentagotai, O. David, S. Ștefan, K. Månsson, D. David, et al.
Internet-delivered cognitive-behavioral therapy for social anxiety disorder in Romania: A randomized controlled trial
Public Library Of Science, 10 (5) (2015), p. e0123997
View PDF
CrossRef View Record in Scopus Google Scholar
van Ballegooijen et al., 2013: W. van Ballegooijen, H. Riper, B. Klein, D. Ebert, J. Kramer, P. Meulenbeek, et al.
An internet-based guided self-help intervention for panic symptoms: Randomized controlled trial
Journal of Medical Internet Research, 15 (7) (2013), p. e154
View PDF
CrossRef View Record in Scopus Google Scholar
Vernmark et al., 2010: K. Vernmark, J. Lenndin, J. Bjärehed, M. Carlsson, J. Karlsson, J. Öberg, et al.
Internet administered guided self-help versus individualized e-mail therapy: A randomized trial of two versions of CBT for major depression
Behaviour Research and Therapy, 48 (5) (2010), pp. 368-376
Article Download PDF View Record in Scopus Google Scholar
Wagner et al., 2014: B. Wagner, A. Horn, A. Maercker
Internet-based versus face-to-face cognitive-behavioral intervention for depression: A randomized controlled non-inferiority trial
Journal of Affective Disorders, 152–154 (2014), pp. 113-121
Article Download PDF View Record in Scopus Google Scholar
Waller, 2009: G. Waller
Evidence-based treatment and therapist drift
Behaviour Research and Therapy, 47 (2) (2009), pp. 119-127
Article Download PDF View Record in Scopus Google Scholar
Warmerdam et al., 2008: L. Warmerdam, A. van Straten, J. Twisk, H. Riper, P. Cuijpers
Internet-based treatment for adults with depressive symptoms: Randomized controlled trial
Journal of Medical Internet Research, 10 (4) (2008), p. e44
View PDF
CrossRef View Record in Scopus Google Scholar
Watts et al., 2015: S. Watts, A. Turnell, N. Kladnitski, J. Newby, G. Andrews
Treatment-as-usual (TAU) is anything but usual: A meta-analysis of CBT versus TAU for anxiety and depression
Journal of Affective Disorders, 175 (2015), pp. 152-167
Article Download PDF View Record in Scopus Google Scholar
Whiteford et al., 2015: H. Whiteford, A. Ferrari, L. Degenhardt, V. Feigin, T. Vos
The global burden of mental, neurological and substance use disorders: An analysis from the global burden of disease study 2010
Public Library Of Science, 10 (2) (2015), p. e0116820
View PDF
CrossRef View Record in Scopus Google Scholar
Williams and Andrews, 2013: A. Williams, G. Andrews
Effectiveness of internet cognitive behavioral therapy (iCBT) for depression in primary care: A quality assurance study
Public Library Of Science, 8 (2013), p. e57447
View PDF
CrossRef View Record in Scopus Google Scholar
Williams et al., 2013: A. Williams, S. Blackwell, A. Mackenzie, E. Holmes, G. Andrews
Combining imagination and reason in the treatment of depression: A randomized controlled trial of internet-based cognitive-bias modification and internet-CBT for depression
Journal of Consulting and Clinical Psychology, 81 (5) (2013), pp. 793-799
View PDF
CrossRef View Record in Scopus Google Scholar
Williams et al., 2014: A. Williams, K. O'Moore, E. Mason, G. Andrews
The effectiveness of internet cognitive behaviour therapy (iCBT) for social anxiety disorder across two routine practice pathways
Internet Interventions, 1 (4) (2014), pp. 225-229
Article Download PDF View Record in Scopus Google Scholar
Wims et al., 2010: E. Wims, N. Titov, G. Andrews, I. Choi
Clinician-assisted internet-based treatment is effective for panic: A randomized controlled trial
Australian & New Zealand Journal of Psychiatry, 44 (7) (2010), pp. 599-607
View PDF
CrossRef View Record in Scopus Google Scholar
Wright et al., 2005: J. Wright, A. Wright, A. Albano, M. Basco, L. Goldsmith, T. Raffield, et al.
Computer-assisted cognitive therapy for depression: Maintaining efficacy while reducing therapist time
American Journal of Psychiatry, 162 (6) (2005), pp. 1158-1164
View PDF
CrossRef View Record in Scopus Google Scholar

1: These authors contributed equally to this work.

2: These authors also contributed equally to this work.

Computer therapy for the anxiety and depression disorders is effective, acceptable and practical health care: An updated meta-analysis