East Asian Arch Psychiatry 2020;30:52-6 | https://doi.org/10.12809/eaap1885

ORIGINAL ARTICLE

Shahrbanoo Ghahari, PhD, Department of Mental Health, School of Behavioral Sciences and Mental Health (Tehran Institute of Psychiatry), Iran University of Medical Sciences, Tehran, Iran
Kourosh Mohammadi-Hasel, PhD, Department of Psychology, Roodehen Branch, Islamic Azad University, Damavand, Iran
Seyed Kazem Malakouti, MD, Department of Social Psychiatry, Center of Excellence in Psychiatry, School of Behavioral Sciences and Mental Health (Tehran Institute of Psychiatry), Iran University of Medical Sciences, Tehran, Iran
Mohsen Roshanpajouh, MD, Addiction Researches Department, Center of Excellence in Psychiatry, School of Behavioral Sciences and Mental Health (Tehran Institute of Psychiatry), Iran University of Medical Sciences, Tehran, Iran

Address for correspondence: Mohsen Roshanpajouh, Addiction Researches Department, Center of Excellence in Psychiatry, School of Behavioral Sciences and Mental Health (Tehran Institute of Psychiatry), Iran University of Medical Sciences, Tehran, Iran
roshanpajouh.m@iums.ac.ir

Submitted: 3 October 2018 Accepted: 9 January 2020 

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Introduction

Generalised anxiety disorder (GAD) is characterised by extreme and uncontrollable worries and is associated with other anxiety disorders, depression, and a range of physical health disorders.¹ GAD often occurs in early adulthood and is twice as likely to occur in women as in men.² The prevalence of GAD in the Iranian population aged 18 to 65 years is 2.5%³ and 0.6% to 4.3% in other countries. The risk of its lifetime prevalence is 9%.⁴ GAD has more harmful effects than other anxiety disorders on physical and mental health and quality of life.^5,6 All these disorders use considerable healthcare services and cause functional disruptions.⁷

Pharmacotherapy is the first treatment option.^8,9 However, it is associated with a relatively high rate of relapse and uncertain lasting effects after discontinuation of medication.^10,11 Thus, psychological treatments are necessary.

Mindfulness-based cognitive therapy (MBCT) can reduce general anxiety symptoms and anxiety sensitivity (the main components of GAD), with a specific mental orientation towards experience and awareness about the present time in a non-judgmental style by minimising the involvement in thoughts and feelings.¹² MBCT is effective in treating patients with GAD.¹³ MBCT is an effective adjuvant to pharmacotherapy in patients with panic disorderor GAD.¹⁴ MBCT is more efficacious than a training programme for treating anxiety disorder.¹⁵ Therefore, we conducted a meta-analysis on the effectiveness of MBCT on GAD.

Methods

The PRISMA guideline for reporting systematic reviews and meta-analyses was used.¹⁶ Inclusion criteria for studies were: (1) randomised controlled trials, randomised trials, cluster randomised controlled trials, and clinical trials of MBCT for the treatment of GAD reported in English or Persian languages and published in peer-reviewed journals. (2) Participants aged ≥18 years diagnosed with GAD or GAD symptoms according to any diagnostic classification system who underwent MBCT, with anxiety scores measured according to a standard test.

Two authors independently performed the eligibility, quality assessment, and data extraction processes, and consensus was reached in case of discrepancies. Electronic databases (PsycINFO, PubMed, Embase, ProQuest, Scopus, Web of Science, Google Scholar, and Medline) were searched for eligible studies up to November 2018 using keywords: mindfulness-based cognitive therapy OR mindfulness based cognitive therapy OR MBCT AND general anxiety disorder OR GAD*. Papers in clinical psychology journals and other journals that had the most relevant early studies were also searched manually. In addition, reference lists of found articles and other reviews were inspected, and leading researchers in the field of MBCT were contacted to identify further relevant studies. Duplicates were removed from the total number of identified records. Abstracts from the remaining records were screened to retrieve full-text articles for assessment of eligibility. Studies fulfilling inclusion criteria were selected for meta-analytic evaluation. The retrieval process was checked by authors.

A data extraction sheet was developed for participant 

characteristics (including age, sex, baseline anxiety score, and medication), group characteristics (including intervention, comparison condition, number of group participants and dropouts, and use of non-study treatments for anxiety within groups), and diagnosis and therapeutic characteristics (including diagnostic classification system, length of sessions and therapy period).

The methodological quality of studies was assessed using the revised Jadad scale based on six criteria: (1) the study was described as randomised; (2) the randomisation procedure was described and appropriate, ie, study participants were randomly allocated independent of the investigators “by methods allowing each participant to have the same chance of receiving each intervention”; (3) blind outcome assessments were reported (blindness of participants and therapists, as required by the original Jadad criteria, are not possible); (4) the blinding method was appropriate, (5) the number and reasons of withdrawals and dropouts were provided for each group, and (6) there was a description of inclusion/exclusion criteria. One point was assigned for each of the six fulfilled criteria; the maximum Jadad score was 6. Disagreements between raters were resolved by discussion.

Statistical analyses were conducted using the STATA (version 16). Forest plot statistics and a funnel plot of individual study effect sizes were used for detecting potential biases in the publication of study results.

Results

The flowchart for the inclusion process of studies is shown in Figure 1. The title and methodology of each eligible study were independently assessed. Of 203 papers evaluated, 197 were excluded owing to repetition (n = 38), MBCT not being used or no inclusion criteria (n = 149), or not conducted specifically for GAD (n = 10). The remaining six studies that compared the effectiveness between MBCT and controls were included for analysis.^14,15,17-20

Among the six studies, the sample sizes ranged from 11 to 182; the mean age of participants ranged from 32 to 50 years; and percentage of women ranged from 0% to 79% (Table 1). The assessment tool used was the Beck Anxiety Index. The diagnosis of GAD was made according to the DSM-IV. The mean revised Jadad score of the six studies was 4.3 (range, 3-6) [Table 2].

Effect sizes (Hedge’s g) and weights of six studies are shown in Figure 2. The overall sample size was 403. Effect sizes varied from -0.017 to -1.07, with an overall mean of -0.65 (95% confidence interval, -0.97 to -0.32; z = -3.93, p = 0.001). Heterogeneity was considerable (I² = 49.96). This effect (d = 0.65) was significant (p < 0.001) and can be considered as a good effect indicating that the finding is robust. The fail-safe N analysis indicated that 14 missing equal sample size studies with no effect of MBCT compared with controls (ie, a risk ratio of 1.0) would be needed to reduce the overall risk of relapse effect size to a non- significant level (p > 0.05). The funnel plot of effect sizes in relation to the effect size standard error had a symmetrical distribution (Figure 3).

Discussion

In the present meta-analysis, the overall risk ratio for GAD in MBCT versus controls was 0.65, which indicates that MBCT is an effective intervention for GAD. The methodological quality of the six studies was high, with a mean revised Jadad score of 4.3. There was no evidence of publication bias according to tests of funnel plot. Fourteen missing studies of comparable sample size with an effect size of zero would be needed to nullify the result. Therefore, this meta-analysis is considered credible. Evidence of heterogeneity between individual studies can be neglected because of vast cultural differences between countries of studies.

A study of the effect of MBCT on GAD reported significant improvement in pathological concerns, stress, quality of life, and a number of other symptoms that remained after treatment, although the effect size on the improvement of pathologic concerns was very small.²¹ In MBCT, owing to the awareness exercises and being in the moment as well as awareness of physical sensations and psychological sensations, participants realise that when they are anxious, their heart rate and respiration changes. By MBCT, participants focus their attention on their body and thus increase the awareness of the body, feelings, and thoughts associated with anxiety, which increases the sense of symptom controllability, leading to anxiety reduction.

MBCT is effective in the treatment of GAD by integrating elements of philosophy, dialectics, mindfulness, acceptance, and communication, and taking advantage of mediating as a pivotal domain, as well as focusing on attention control in the treatment.²²

The present study has some limitations. The number of studies included was small. The quality and type of methodology of the studies differed. In some studies, the MBCT group was compared with the non-intervention group, whereas in other studies, the MBCT group was compared with other-treatment group. This complicated the analysis and limited the power of results.²³ In addition, the present study did not report the required data in the studies. In case of no access to full paper, the abstracts of studies were excluded. There was no access to some information sources and some required papers.

Conclusion

MBCT was effective for treating GAD.

Declaration

The authors have no conflict of interest to disclose.

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