Internet-based cognitive and behavioural therapies for post-traumatic stress disorder (PTSD) in adults

Therapist-delivered trauma-focused psychological therapies are effective for post-traumatic stress disorder (PTSD) and have become the accepted first-line treatments. Despite the established evidence-base for these therapies, they are not always widely available or accessible. Many barriers limit treatment uptake, such as the number of qualified therapists available to deliver the interventions; cost; and compliance issues, such as time off work, childcare, and transportation, associated with the need to attend weekly appointments. Delivering Internet-based cognitive and behavioural therapy (I-C/BT) is an effective and acceptable alternative to therapist-delivered treatments for anxiety and depression.

To assess the effects of I-C/BT for PTSD in adults.

We searched MEDLINE, Embase, PsycINFO and the Cochrane Central Register of Controlled Trials to June 2020. We also searched online clinical trial registries and reference lists of included studies and contacted the authors of included studies and other researchers in the field to identify additional and ongoing studies.

We searched for RCTs of I-C/BT compared to face-to-face or Internet-based psychological treatment, psychoeducation, wait list, or care as usual. We included studies of adults (aged over 16 years), in which at least 70% of the participants met the diagnostic criteria for PTSD, according to the Diagnostic and Statistical Manual (DSM) or the International Classification of Diseases (ICD).

Two review authors independently assessed abstracts, extracted data, and entered data into Review Manager 5. The primary outcomes were severity of PTSD symptoms and dropouts. Secondary outcomes included diagnosis of PTSD after treatment, severity of depressive and anxiety symptoms, cost-effectiveness, adverse events, treatment acceptability, and quality of life. We analysed categorical outcomes as risk ratios (RRs), and continuous outcomes as mean differences (MD) or standardised mean differences (SMDs), with 95% confidence intervals (CI). We pooled data using a fixed-effect meta-analysis, except where heterogeneity was present, in which case we used a random-effects model. We independently assessed the included studies for risk of bias and we evaluated the certainty of available evidence using the GRADE approach; we discussed any conflicts with at least one other review author, with the aim of reaching a unanimous decision.

We included 13 studies with 808 participants. Ten studies compared I-C/BT delivered with therapist guidance to a wait list control. Two studies compared guided I-C/BT with I-non-C/BT. One study compared guided I-C/BT with face-to-face non-C/BT. There was substantial heterogeneity among the included studies. I-C/BT compared with face-to-face non-CBT Very low-certainty evidence based on one small study suggested face-to-face non-CBT may be more effective than I-C/BT at reducing PTSD symptoms post-treatment (MD 10.90, 95% CI 6.57 to 15.23; studies = 1, participants = 40). There may be no evidence of a difference in dropout rates between treatments (RR 2.49, 95% CI 0.91 to 6.77; studies = 1, participants = 40; very low-certainty evidence). The study did not measure diagnosis of PTSD, severity of depressive or anxiety symptoms, cost-effectiveness, or adverse events. I-C/BT compared with wait list Very low-certainty evidence showed that, compared with wait list, I-C/BT may be associated with a clinically important reduction in PTSD post-treatment (SMD -0.61, 95% CI -0.93 to -0.29; studies = 10, participants = 608). There may be no evidence of a difference in dropout rates between the I-C/BT and wait list groups (RR 1.25, 95% CI 0.97 to 1.60; studies = 9, participants = 634; low-certainty evidence). I-C/BT may be no more effective than wait list at reducing the risk of a diagnosis of PTSD after treatment (RR 0.53, 95% CI 0.28 to 1.00; studies = 1, participants = 62; very low-certainty evidence). I-C/BT may be associated with a clinically important reduction in symptoms of depression post-treatment (SMD -0.51, 95% CI -0.97 to -0.06; studies = 7, participants = 473; very low-certainty evidence). Very low-certainty evidence also suggested that I-C/BT may be associated with a clinically important reduction in symptoms of anxiety post-treatment (SMD -0.61, 95% CI -0.89 to -0.33; studies = 5, participants = 345). There were no data regarding cost-effectiveness. Data regarding adverse events were uncertain, as only one study reported an absence of adverse events. I-C/BT compared with I-non-C/BT There may be no evidence of a difference in PTSD symptoms post-treatment between the I-C/BT and I-non-C/BT groups (SMD -0.08, 95% CI -0.52 to 0.35; studies = 2, participants = 82; very low-certainty evidence). There may be no evidence of a difference between dropout rates from the I-C/BT and I-non-C/BT groups (RR 2.14, 95% CI 0.97 to 4.73; studies = 2, participants = 132; I² = 0%; very low-certainty evidence). Two studies found no evidence of a difference in post-treatment depressive symptoms between the I-C/BT and I-non-C/BT groups (SMD -0.12, 95% CI -0.78 to 0.54; studies = 2, participants = 84; very low-certainty evidence). Two studies found no evidence of a difference in post-treatment symptoms of anxiety between the I-C/BT and I-non-C/BT groups (SMD 0.08, 95% CI -0.78 to 0.95; studies = 2, participants = 74; very low-certainty evidence). There were no data regarding cost-effectiveness. Data regarding adverse effects were uncertain, as it was not discernible whether adverse effects reported were attributable to the intervention.

While the review found some beneficial effects of I-C/BT for PTSD, the certainty of the evidence was very low due to the small number of included trials. This review update found many planned and ongoing studies, which is encouraging since further work is required to establish non-inferiority to current first-line interventions, explore mechanisms of change, establish optimal levels of guidance, explore cost-effectiveness, measure adverse events, and determine predictors of efficacy and dropout.