Abstract
Depression and anxiety disorders are the common mental disorders (CMDs) affecting around 322 million people worldwide or 4.4% of the global population; CMDs are more common in females (5.1%) than males (3.6%). 1 The prevalence of CMDs in India is about 5.1%, nearly 70 million adults are suffering from CMDs, and urban residents and older adults are more vulnerable to CMDs. 2 In primary care, 25% of patients are diagnosed with primary mental disorders, also having comorbid depression and anxiety disorders. 3 Additionally, approximately 90% of patients diagnosed with anxiety disorders have also been diagnosed with comorbid depressive disorders. Conversely, 85% of patients with depression also have significant anxiety-related conditions. 4
Mindfulness-based cognitive therapy (MBCT) is drawn primarily from cognitive behavioral therapy (CBT), mindfulness-based stress reduction, and interacting cognitive subsystems. 5 This evidence-based therapeutic approach was designed by Segal et al. 6 primarily to treat depressive disorder. MBCT helps patients by radically shifting from their thoughts, feelings, and body sensations that contribute to depressive relapses. 6 MBCT is effective in reducing anxiety symptoms 7 and the risk of depression relapse compared with treatment with antidepressants alone. 8 MBCT is also recommended to treat people with chronic physical health problems having comorbid depressive disorder. 9
Recently, many randomized control trials (RCTs) have demonstrated the effectiveness of MBCT in the treatment of stress, depression, and anxiety,10–12 recurrence of depressive episodes,8,13 depression and anxiety in women with premenstrual syndrome, 14 and anxiety and depression in breast cancer patients. 15
Further, systematic reviews and meta-analytic studies have been conducted to demonstrate the effectiveness of MBCT. It is reported to be effective in reducing the symptoms of patients with major depressive disorder with suicidal ideation, 16 social anxiety disorder,17,18 generalized anxiety disorder, 19 depression and anxiety, 20 recurrent major depressive disorder, 21 and psychological well-being. 20 In another meta-analysis review, Li et al. 22 compared the effectiveness of mindfulness-based interventions and CBT in treating anxiety, depression, and sleep quality. They reported similar treatment effectiveness for both treatment methods. However, including a small number of studies was a significant limitation of many meta-analytical findings,16,17,19,21 which further limits the generalizability of the findings.
Further, in a systematic review, Thomas et al. 23 restricted to include the elderly participants only to measure the effectiveness of MBCT in the treatment of anxiety and depressive disorders. Most meta-analytical studies have reported the effectiveness of MBCT based on pre- and post-therapeutic observations and assessments, only another major limitation of these meta-analytical studies. Therefore, based on these findings, the temporal longevity of the effectiveness of MBCT cannot be ensured. Only Liu et al. 18 have reported the durability of MBCT in the management of social anxiety disorder with a limited number of studies.
Henceforth, this systematic review and meta-analysis aim to assess the effectiveness of MBCT in managing anxiety and depression and provide an update on the current knowledge.
Method
Protocol Preregistration
This study was registered with PROSPERO under the registration number CRD42023465494 and was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.
Data Sources and Search Strategy
We searched PubMed, Web of Science, EBSCOhost, Ovid, Scopus, and JSTOR for relevant research papers until September 16, 2023. The search terms used were “mindfulness-based cognitive therapy” or “MBCT” and “depression or depressive disorder” or “depressive and anxiety” or “anxiety disorder” or “anxiety and depression” and “randomized-controlled trial or random* or RCT.” The articles were limited to being searched in English and published in peer-reviewed journals. Duplication of the articles was detected using HubMeta (
Eligibility Criteria
Inclusion Criteria
Only RCT-based articles were included where an intervention group and a CG or waitlist (WL) or treatment as usual (TAU) or control trials were designated to investigate the efficacy of MBCT involving participants who were diagnosed with either depression or anxiety disorders or both as per diagnostic criteria of Diagnostic and Statistical Manual of Mental Disorders-IV Text Revision (DSM-IV-TR) and DSM5/International Classification of Diseases (ICD) 10 or 11. The articles comprised participants of both genders between the ages of 18 and 65 years. The group-based MBCT must be delivered in face-to-face mode following the guidelines provided by Segal et al., 6 which were included in the present study. Regarding comparators, inactive control, WL, TAU, etc. were included. Articles published in the English language were only included.
Exclusion Criteria
We excluded the study from non-RCTs, such as controlled clinical trials, quasi-experimental designs, and case studies. We also excluded those studies in which MBCT was used in patients with bipolar disorder, brain injury, schizophrenia, schizoaffective disorder, organic mental disorder, or neurocognitive disorder (e.g., dementia, delirium, Alzheimer’s disease, etc.), as well as in patients with any form of cancer. The studies of internet-based or video-based MBCT were excluded from the present meta-analysis.
Quality Assessment
The risk of bias (RoB) within the RCTs was assessed using the Cochrane Risk-of-Bias 2.0 tool for randomized trials (RoB2, 2019 Version). The following five domains for randomized trials were assessed: (a) bias arising from the randomization process, (b) bias owing to deviations from intended interventions, (c) bias caused by missing outcome data, (d) bias in the measurement of the outcome, and (e) bias in the selection of the reported result. The Cochrane RoB tool is used to evaluate random sequence generation, allocation concealment, blinding of participants and personnel, blinding of outcome assessment, completeness of outcome data, selective reporting, and other sources of bias (Figure 2).
Data Extraction
Table 1 reports the procedure used for data extraction. The researchers developed a data extraction sheet to extract feature characteristics from the included studies, such as
Characteristics of Included Studies.
RCT: Randomized Controlled Trail; MBCT: Mindfulness-based Cognitive Therapy, CBT: Cognitive Behavioral Therapy; AC: Active Control; ACG: Active Control Group; CG: Control Group; TAU: Treatment As Usual; WL: Waitlist; NF: No Follow-up; BDI: Beck Depression Inventory; BAI: Beck Anxiety Inventory; SHAI: Short Health Anxiety Inventory; DASS-21: Depression Anxiety and Stress Scale-21; HADS-D Hospital Anxiety and Depression Scale-Depression; HADS-A Hospital Anxiety and Depression Scale-Anxiety Scale; BSI: Brief Symptom Inventory; CESDS: Center for Epidemiologic Studies Depression Scale; STAI: State-Trait Anxiety Inventory; HAMD: Hamilton Depression Scale; VASMA: Visual Analog Scale for Measuring Anxiety; GAD-7: Generalized Anxiety Disorder 7 Items; POMS: The Profile of Mood States; IDS-SR: The Inventory of Depressive Symptomatology Self-Report; IDS-SR: Inventory of Depressive Symptomatology Self-Report.
Results
Study Selection
The original search results in 2044 studies were found through an electronic search of 6 databases, and 569 duplicate studies were removed. After carefully examining titles and abstracts, 1324 studies that did not meet the inclusion criteria were excluded. In the first phase of the eligibility screening, 146 studies were screened according to the inclusion and exclusion criteria. After a full-text review, 125 studies were excluded, and 21 were found eligible. In the final phase, 21 studies were included in the review process. The selection process is shown in the flow diagram in Figure 1.
PRISMA Flowchart (2020) of the Inclusion Process of Studies.
Characteristics of the Studies
The characteristics of the 21 included studies that published between 2003 and 2023 are summarized in Table 1. The studies were published in various countries. The types of CGs include TAU, WL, CBT, and other interventions. Seven studies compared MBCT with TAU, six studies compared MBCT with a WL, four studies compared MBCT with CBT, two studies compared MBCT with an active control group (ACG), one study compared MBCT with the CG, and one study compared MBCT with psychoeducation (see Table 1).
Risk of Bias of the Studies
Figure 2 demonstrates the RoB for the included RCTs. Most studies (i.e., 19 studies) included in the present meta-analysis were rated as having a low RoBs across most domains, suggesting robust study designs were implemented in the included studies. However, three studies24–26 were rated as raising concerns in some domains. Therefore, most studies demonstrated a low RoB, as shown in Figure 2.
Risk of Bias (RoB2.0) Summary for the Included Studies in the Meta-analysis.
Intervention Characteristics and Outcome Measures
Treatments implemented in various types of research exhibit similarities in the structure of MBCT. In all the studies in the present meta-analysis, the standard MBCT was implemented with weekly sessions over eight weeks, each lasting 2 to 2.5 hours. The CGs comprised WL, TAU, and ACG. The most common measures for depression and anxiety were the Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), Depression, Anxiety and Stress Scale (DASS-21), and Hamilton Depression Scale (HAMD) (see Table 1).
Meta-analysis
The meta-analysis was conducted through the R 4.2.1 software using “meta,” 45 “metafor,” 46 and “dmetar” 47 packages. All statistical tests were conducted at a significance level of 5% (two-tailed tests). In particular, using the “metafor” package, all the studies’ effect sizes and standard errors were calculated using the cmicalc() function. Further, the metagen() function was used to synthesize estimated effect sizes and standard errors. All the studies are based on pre-test, post-test, and CG design, and most of the studies provided mean and standard deviations of both pre-, post-, and follow-up assessment measures of treatment group (TG) and CG. The effect size and standard errors for both baseline and post-therapeutic comparisons and post- and follow-up therapeutic comparisons for anxiety and depressive symptoms were computed using the convention provided by Morris et al. 48 . In some studies, wherein the effect size and 95% CI of the effect size were reported, the standard errors of studies were estimated accordingly. The forest plot was created using the forest() function. To measure the presence of possible publication bias in the present meta-analysis, the funnel() function was used. Finally, a sensitivity analysis was performed to remove influential and outlier studies that could bias the effect size estimate and precision. 47 To perform a sensitivity analysis, the functions “find.outliers()” and “InfluenceAnalysis()” of the package were used. 47
Efficacy of MBCT in the Treatment of Depression and Anxiety
The meta-analysis included 19 studies (
Forest Plot Representing Comparison of Pre-intervention and Post-intervention Depression Scores of MBCT vs Tau.
Pooled Effect Sizes for MBCT and Control Conditions for the Management Depression and Anxiety.
A total of 14 studies used in the present meta-analysis demonstrate the effectiveness of MBCT in treating anxiety disorders (Figure 4, Table 2). Results of comparisons between pre-therapeutic and post-therapeutic conditions of anxiety-related symptoms show that MBCT contributes to a significant symptom reduction in the TG compared to TAUs (SMD = −0.3817,
Forest Plot Representing Comparison of Pre-intervention and Post-intervention Anxiety Scores of MBCT vs Tau.
Durability of MBCT in the Treatment of Depression and Anxiety Disorders
A total of 10 studies compared the level of depression between the TG and the CG in the post-therapeutic phase and in the follow-up phase (Table 2, Figure 5). Findings suggest that improved depressive symptoms through MBCT are maintained until follow-up assessment (SMD = 0.0130,
Forest Plot Representing Comparison of Post-intervention and Follow-Up Depression Scores of MBCT.
Similarly, only nine studies compared the level of anxiety between the TG and the CG in the post-therapeutic and follow-up phases of the studies (Table 2, Figure 6). Findings based on nine studies suggest that reduced levels of symptoms of anxiety in the post-therapeutic assessment were maintained to a similar degree till the follow-up assessment, and in the CG, the level of anxiety assessed in the post-assessment phase remained the same compared to the assessment done in the follow-up phase (Figure 6). It can be further inferred from the findings that improved anxiety symptoms through MBCT were maintained till the follow-up assessment (SMD = −0.0660,
Forest Plot Representing Comparison of Post-intervention and Follow-Up Anxiety Scores of MBCT.
A series of Egger’s regression tests
49
were performed to estimate the possible presence of publication bias for the studies representing the efficacy of MBCT in the management of depression and anxiety disorders. The obtained intercept (β0) values were 5.5296 (
The “InfluenceAnalysis()” function is used to conduct influence diagnostics by leave-one-out meta-analysis results for the pre-therapeutic and post-therapeutic comparisons for both anxiety and depressive disorders sorted by their effect size
47
. Further, the Baujat plot
50
detects studies that overly contribute to heterogeneity in a meta-analysis. It is evident from the leave-one-out meta-analysis (
Sensitivity Analysis for Depressive Disorders.
1Influential studies removed: Shallcross et al. (2015), Assumpcao et al. (2023), Geschwind et al. (2012), Tovote et al. (2014), Omidi et al. (2013).
2Outliers removed: Omidi et al. (2013), Geschwind et al. (2012), Musa et al. (2020), Tovote et al. (2014), Shih et al. (2021), Assumpcao et al. (2023), Chiesa at al. (2012), Manicavasgar et al. (2010), Shallcross et al. (2015).
Sensitivity Analysis for Anxiety Disorders.
1Influential studies removed: Omidi et al. (2013), van Son et al. (2014), Manicavasgar et al. (2010).
2Outliers removed: Omidi et al. (2013), Ninomiya et al. (2020), van Son et al. (2014), Manicavasgar et al. (2010).
Discussions
The findings of the present study indicate that eight weeks of MBCT significantly reduced symptoms of both anxiety and depression, and reduced anxiety and depressive symptoms were maintained until follow-up. The present findings are aligned with previously reported meta-analytical findings that have also reported that MBCT is effective in the management of various anxiety and depression-related clinical conditions, such as social anxiety disorder,17,18 generalized anxiety disorder, 19 and depression and anxiety, 20 and recurrent major depressive disorder. 21 In a network meta-analysis-based study, McCartney et al. 51 also found the effectiveness of MBCT as a preventative treatment in the management of recurrent depression.
The findings of the present study suggest that MBCT produces long-term treatment effects in the management of both anxiety and depressive disorders. The present findings are similar to the meta-analytical findings of Liu et al. 18 , who have reported the long-term effectiveness of MBCT in the management of social anxiety disorder. However, there is a scarcity of literature to measure long-term efficacy in the management of the symptoms of anxiety and depression. Similarly, in a network meta-analytical-based study, McCartney et al. 51 reported the long-term treatment effectiveness of MBCT in preventing depression replacement.
The results also suggest significant heterogeneity present across the findings evaluating the effectiveness of MBCT in the management of anxiety and depressive disorders. Heterogeneity can be preceded by differences in diagnostic tools, diagnostic criteria, the setting, severity of the patients, etc, in the conducted RCTs. Also, there is an absence of publication bias in the present meta-analysis, as the present meta-analysis is based on 21 RCTs.
Findings of sensitivity analysis, such as influential and outlier analysis, suggest that stability is present across the findings evaluating the effectiveness of MBCT. We have removed both types of studies that have highly contributing effect sizes and a high degree of variability. Even after removing both types of studies, MBCT was found effective in the management of depression and anxiety disorders. We did not perform sensitivity analysis for studies measuring the long-term effectiveness or durability of MBCT, as a smaller number of studies reported both depression and anxiety.
The present meta-analysis is one of the first attempts to analyze both the efficacy and durability of MBCT in the treatment of anxiety and depressive disorders. Despite its strength being the inclusion of a wide range of RCTs and interventions from six online databases, the study also has certain limitations. For instance, in almost all RCTs, patients received antidepressant and anxiolytic medications in addition to receiving MBCT. Almost all studies did not describe the type and dosage of medications used to treat patients along with MBCT. Therefore, there is a possible moderating effect of the type and dosage of both anxiolytic and antidepressant medications on the recovery process of patients that we did not control in the present study. Although we assumed that the same medical team would treat both TG and CG participants owing to randomization, there are similarities in the conditions of pharmacological treatment within the study.
Modality and the number of sessions of MBCT could also be possible sources of biases and errors while computing pooled SMD of all studies. To control this bias, we only included those studies that implemented MBCT in eight sessions within eight weeks. Additionally, all the sessions were implemented through face-to-face mode only. Although MBCTs implemented through internet-based or video-based studies were excluded from the present meta-analysis, it could be a possible source of publication bias. As the number of studies in the present meta-analysis is limited, we could not estimate the efficacy of the MBCT disorder subtypes.
Conclusion
The present study was one of the first attempts to evaluate the effectiveness and durability of MBCT and found that it is practical and durable in treating anxiety and depressive disorders. Therefore, this therapeutic procedure is recommended as an adjunct to conventional pharmacotherapy to treat both disorders. The findings on the long-term effectiveness of MBCT are still preliminary, as they are based on limited studies.
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Footnotes
Declaration of Conflicting Interests
Declaration Regarding the Use of Generative AI
Funding
References
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