Commentary on selected evidence
With advice from topic experts we selected 1 study for further commentary.
We selected the systematic review by Norton et al. (2015) for a full commentary because it includes a relevant population and intervention. Also, the study reinforces guideline recommendations that mindfulness-based interventions should not be routinely offered.
NICE guideline CG159 does not recommend mindfulness-based interventions to treat social anxiety disorder (recommendation 1.6.3). This includes mindfulness-based stress reduction and mindfulness-based cognitive therapy.
The Norton et al. (2015) systematic review investigated the efficacy of mindfulness- and acceptance-based interventions for treating social anxiety disorder. A literature search within PsycINFO, Medline, PubMed, Cochrane Central Register of Controlled Trials and reference lists was conducted to identify relevant English-language articles. The selection criteria included all study designs, including uncontrolled studies, with quantitative statistical analyses for an adult population aged 18 to 65 years. The included studies were required to specifically investigate mindfulness- and acceptance-based interventions for social anxiety disorder. No restrictions on sample size were applied to included studies. The systematic review used 2 reviewers to code abstracts for inclusion and assess risk of bias with the Cochrane risk of bias tool.
The systematic review identified a total of 11 studies meeting the inclusion criteria. Of these, 2 pairs of articles contained the same participant samples and were combined for analyses. This resulted in 9 separate samples containing a total of 380 participants across 4 randomised controlled trials and 5 uncontrolled trials. Group interventions formed the primary focus of 7 studies and individual interventions in 2 studies. Outcomes varied across studies and included: symptoms, processes, functional impairment and quality of life. Outcome measures also varied with the use of Anxiety Disorders Interview Schedule for DSM‑IV, Fear of Negative Evaluation Scale, Mini International Neuropsychiatric Interview, Structured Clinical Interview for DSM, and the Social Anxiety Disorders and Anxiety Inventory. All studies measured outcomes at pre- and post-treatment and 7 studies also included follow‑up assessments ranging between 2 and 6 months.
Mindfulness-based stress reduction (MBSR) was the primary intervention in 3 studies, all of which found significant improvements for MBSR in all outcomes at post-treatment. Follow-up was assessed in 1 of the studies and indicated that significant improvements for MBSR were maintained at 3 months. However, it was also found that outcomes significantly improved with group cognitive behaviour therapy (CBGT) compared to MBSR.
Mindfulness-based cognitive therapy (MBCT) was the primary intervention in 2 studies, which both found significant improvements for MBCT in social anxiety symptoms at post-treatment and follow‑up at 2 months and 6 months. One study found no significant differences in social anxiety symptoms between CBGT and MBCT.
Acceptance and commitment therapy (ACT) was the primary intervention in 2 studies, which both found significant improvements for ACT in social anxiety symptoms at post-treatment and follow‑up at 3 months.
Mindfulness- and acceptance-based group therapy (MAGT) was the primary intervention in 2 studies, which both found significant improvements for MAGT in social anxiety symptoms at post-treatment and follow‑up at 3 months. One study found no significant differences for any outcome between CBGT and MAGT.
The target population in the study is relevant to the population in NICE guideline CG159. The study clearly defines the population as adults with a diagnosis of social anxiety disorder. Although NICE guideline CG159 also includes children and young people, the inclusion of adults in the study is relevant.
Methodologically, this study used an appropriate search strategy to identify relevant articles from a range of sources. Quality assurance in study selection was adequate with the use of an appropriate risk of bias tool used by multiple reviewers.
The systematic review has a number of methodological limitations that potentially reduce the reliability of the results. The review included uncontrolled studies that are weak in design and this seriously limits the strength of the results. The review did not provide any evidence indicating attempts were made to minimise errors in data collection. Some details of included studies were tabulated and outlined in the study manuscript; however, no information was provided about the demographic characteristics of participants in the studies. The review stated the categories of outcomes that were assessed (for example, social anxiety) but it did not specify what outcome measures were used to assess the individual outcomes. Also no detail was provided on any of the scoring systems for the outcome measures, which may have given an indication of clinical meaning to the results.
The review reports minimal statistical data from the included studies with only effect sizes for main outcomes presented. Significance in differences between and within groups are reported; however, no statistical data, such as p values or confidence intervals, to quantify these are provided. The review did not provide any information on the statistical methods used to pool data from included studies. As a result, it was not possible to determine if the analyses were appropriate. The review reported that the overall risk of bias across included studies was high and stated that this was sufficient enough to affect interpretation of the results. Minimal information was provided as to how potential biases were taken into account. A brief interpretation of the results is provided, which was not sufficient to dispel any concerns about the study's methods, analyses or biases of included studies.
NICE guideline CG159 recommends that mindfulness-based interventions should not be routinely offered to treat social anxiety disorder. Although this study highlights the potential benefits of mindfulness- and acceptance-based approaches, there are considerable omissions from the study manuscript and methodological limitations, which reduce the reliability of the results. As such, the effectiveness of mindfulness-based interventions remains unclear from this study. The results are unlikely to impact on current recommendations.
This page was last updated: 22 June 2017