Mindfulness involves paying deliberate attention to the present moment with a non-judgmental attitude.
Mindfulness-based programs, such as Mindfulness-Based Cognitive Therapy (MBCT) and Mindfulness-Based Stress Reduction (MBSR), typically involve an 8-week group-based intervention that includes mindfulness meditation practices, such as body scans, mindful breathing, and gentle yoga.
These programs aim to cultivate mindfulness skills to help individuals relate differently to their thoughts, feelings, and bodily sensations.
For individuals with Generalized Anxiety Disorder (GAD), characterized by persistent and excessive worry, mindfulness-based interventions may help reduce anxiety symptoms by promoting a more present-focused and accepting awareness of one’s experiences, thereby reducing the impact of worry and rumination.
Williams, M., Honan, C., Skromanis, S., Sanderson, B., & Matthews, A. J. (2024). Psychological outcomes and mechanisms of mindfulness-based training for generalised anxiety disorder: A systematic review and meta-analysis. Current Psychology: A Journal for Diverse Perspectives on Diverse Psychological Issues, 43(6), 5318–5340. https://doi.org/10.1007/s12144-023-04695-x
Key Points
- Mindfulness training programs may be effective in reducing anxiety symptoms among those experiencing Generalized Anxiety Disorder (GAD), but may not result in greater symptom reduction than psychoeducation programs that do not include mindfulness practices.
- Mindfulness-based programs appear to provide additional benefits by changing aspects of underlying central nervous system and endocrine system functioning associated with GAD.
- The current literature suggests that gains in aspects of trait mindfulness may be important for anxiety symptom reduction following mindfulness training in GAD.
- The research, while enlightening, has certain limitations, such as a high risk of bias, low certainty of the evidence, and lack of trials using non-manualized or ‘stand-alone’ mindfulness interventions.
Rationale
Generalized Anxiety Disorder (GAD) is a chronic condition characterized by persistent anxiety and worry, with approximately 6% of the population experiencing GAD during their lifetime (ABS, 2008; Newman et al., 2013).
While Cognitive Behavioral Therapy (CBT) is currently the gold standard treatment for GAD (NICE, 2020), up to 50% of patients with an anxiety disorder do not reach full remission (Springer et al., 2018).
Additionally, factors such as financial cost, delivery mode, and client treatment preference present barriers to accessing face-to-face therapies (Andersson & Titov, 2014; Wolitzky-Taylor et al., 2018). Mindfulness-based interventions offer an alternative to CBT and involve practices that are accessible and affordable (Gál et al., 2021).
Previous reviews have found moderate-large effects of mindfulness training interventions on anxiety symptoms but have tended to use mixed anxiety disorder samples or not report differences due to control type (e.g., Ghahari et al., 2020; Strauss et al., 2014; Vøllestad et al., 2012).
The current review aimed to deepen understanding of mechanisms involved in mindfulness-based interventions for samples experiencing generalized anxiety symptoms (clinical and sub-clinical), which is critical to the further development of accessible and effective treatment options for this population.
Method
This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Page et al., 2021) and Cochrane recommendations (Higgins et al., 2022).
The review included studies with participants aged between 17 and 70 years, assessed as having high levels of general, generalized, or trait anxiety or a GAD diagnosis.
Mindfulness-based training interventions needed to comprise at least two separate sessions over a specified period and include a substantial mindfulness component (>70% mindfulness practice).
Studies were included if they reported at least one anxiety or attention outcome measured at both pre- and post-intervention.
Search Strategy and Terms:
Three databases (Web of Science, Scopus, PsycINFO via Ovid) were searched, with the last search conducted on 25th November 2021.
Search terms for three concepts were used: anxiety (“anxiety” OR “anxious”), mindfulness (“mindful*” OR “focused breathing” OR “breath focus” OR “raisin exercise” OR “breathing space” OR “present moment awareness” OR “body scan”), and intervention (“treatment” OR “intervention” OR “therapy” OR “program” OR “practice” OR “induction” OR “strategy” OR “technique” OR “training” OR “psychotherapy” OR “acute” OR “brief” OR “session” OR “exercise”).
Inclusion and Exclusion Criteria:
Studies were included if they were: (1) a full-text study article, (2) written in English, (3) published in a peer-reviewed journal, and (4) included a control or comparison group.
Studies were excluded if participants were selected based on another type of anxiety or psychological disorder, recent or current pregnancy, or a current or previous medical, developmental, or neuropsychological condition.
Interventions largely comprising other treatment approaches or non-mindfulness therapeutic elements were excluded.
Statistical Measures:
For pre-post intervention effects, standardized mean difference (SMD) effect sizes (Hedge’s g) between the mindfulness and control conditions were calculated with 95% confidence intervals.
Pairwise meta-analyses using random-effects models with restricted maximum-likelihood were conducted if at least two studies reported the same pre-post outcome.
Between-study heterogeneity was assessed using the I2 statistic, Q-statistic, and T2 statistic.
Risk of bias was assessed using the revised Cochrane ‘Risk of bias’ tool for randomized trials (RoB 2.0) and the Risk of Bias in Non-randomized Studies – of Interventions (ROBINS-I) assessment tool.
The quality of evidence for all outcomes was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) method.
Results
The review included eight articles comprising four independent studies (N=334). All studies included participants diagnosed with GAD who participated in an 8-week manualized mindfulness program.
Pooling of three studies revealed a statistically significant reduction in self-reported anxiety symptoms following MBSR/MBCT compared to inactive/non-specified controls, with a very large effect (SMD=-1.92, 95%CI[-3.44, -0.40]).
However, reductions in anxiety following MBSR/MBCT did not significantly differ when compared to active controls.
The narrative review found evidence of reductions in hormonal (ACTH) and immunological (TNF-alpha, IL-6) markers of acute stress and increased connectivity between the amygdala and frontal cortex regions following MBSR compared to active control.
Increased activity in frontal cortex regions and increased connectivity between regions of the Default Mode Network following MBCT were also found compared to active and waitlist controls, respectively.
The narrative review also found evidence that changes in aspects of trait mindfulness mediate anxiety reduction following mindfulness training.
Insight
The findings suggest that 8-week mindfulness training programs can significantly reduce anxiety symptoms in individuals with GAD, with effects comparable to those of psychoeducation programs.
However, mindfulness-based programs appear to provide additional benefits by targeting underlying brain-circuitry mechanisms and stress-related endocrine functioning implicated in GAD.
The review also found evidence that gains in trait mindfulness, particularly the ability to observe thoughts and feelings with distance (i.e., decentering), may be important for anxiety symptom reduction following mindfulness training in GAD.
These findings extend previous research by providing a deeper understanding of the potential mechanisms involved in mindfulness-based interventions for GAD specifically.
Future research could further clarify the distinct therapeutic mechanisms of mindfulness-based programs by including ‘stand-alone’ interventions and evidence-based treatment controls (i.e., CBT) in trials.
Strengths
The study had many methodological strengths, including adherence to PRISMA guidelines and Cochrane recommendations, pre-registration of the protocol, and the use of standardized risk of bias and certainty of evidence assessment tools.
The review also employed a comprehensive search strategy across multiple databases and included studies with both active and inactive control groups, allowing for a more nuanced understanding of the effects of mindfulness training interventions.
Limitations
The review had several limitations, including a small number of eligible independent studies, high risk of bias, and low certainty of evidence across studies.
Two of the four independent studies did not report information relating to current or past meditation experience or intervention adherence, introducing potential threats to internal validity.
The stringent criteria regarding the degree of mindfulness practice required in training interventions (>70%) and the exclusion of interventions largely comprising other treatment approaches may have limited the number of eligible studies.
Additionally, the requirement for studies to have both a pre-post outcome and control group likely restricted the inclusion of other potentially relevant studies for the review’s second objective (predictors, mediators, and moderators of mindfulness training outcomes in anxious individuals).
Implications
The findings of this review have important implications for healthcare providers and consumers.
The results suggest that 8-week manualized mindfulness programs may be as effective as psychoeducation programs in reducing self-reported anxiety in GAD, with gains potentially maintained for up to 9 months post-intervention.
However, mindfulness-based programs may offer additional benefits by targeting underlying central nervous system and endocrine system functioning associated with GAD.
These findings highlight the potential of mindfulness training as an accessible and effective treatment option for individuals with GAD.
Further research utilizing objective measures and including ‘stand-alone’ mindfulness interventions and techniques compared to other evidence-based treatments is needed to better understand how mindfulness training can be effectively tailored to those experiencing symptoms of GAD.
References
Primary reference
Williams, M., Honan, C., Skromanis, S., Sanderson, B., & Matthews, A. J. (2024). Psychological outcomes and mechanisms of mindfulness-based training for generalised anxiety disorder: A systematic review and meta-analysis. Current Psychology: A Journal for Diverse Perspectives on Diverse Psychological Issues, 43(6), 5318–5340. https://doi.org/10.1007/s12144-023-04695-x
Other references
Andersson, G., & Titov, N. (2014). Advantages and limitations of Internet-based interventions for common mental disorders. World Psychiatry, 13(1), 4–11. https://doi.org/10.1002/wps.20083
Gál, E., Stefan, S., & Cristea, I. A. (2021). The efficacy of mindfulness meditation apps in enhancing users’ well-being and mental health related outcomes: A meta-analysis of randomized controlled trials. Journal of Affective Disorders, 279, 131–142. https://doi.org/10.1016/j.jad.2020.09.134
Ghahari, S., Mohammadi-Hasel, K., Malakouti, S. K., & Roshanpajouh, M. (2020). Mindfulness-based Cognitive Therapy for Generalised Anxiety Disorder: A systematic review and meta-analysis. East Asian Archives of Psychiatry, 30(2), 52–56. https://doi.org/10.12809/eaap1885
NICE (National Institute for Health and Care Excellence) (2020). Generalized anxiety disorder and panic disorder in adults: Management. https://www.nice.org.uk/guidance/cg113
Springer, K. S., Levy, H. C., & Tolin, D. F. (2018). Remission in CBT for adult anxiety disorders: A meta-analysis. Clinical Psychology Review, 61, 1–8. https://doi.org/10.1016/j.cpr.2018.03.002
Strauss, C., Cavanagh, K., Oliver, A., & Pettman, D. (2014). Mindfulness-based interventions for people diagnosed with a current episode of an anxiety or depressive disorder: a meta-analysis of randomised controlled trials. PloS one, 9(4), e96110. https://doi.org/10.1371/journal.pone.0096110
Vøllestad, J., Nielsen, M. B., & Nielsen, G. H. (2012). Mindfulness-and acceptance-based interventions for anxiety disorders: A systematic review and meta-analysis. British Journal of Clinical Psychology, 51(3), 239–260. https://doi.org/10.1111/j.2044-8260.2011.02024.x
Wolitzky-Taylor, K., Fenwick, K., Lengnick-Hall, R., Grossman, J., Bearman, S. K., Arch, J., Miranda, J., & Chung, B. (2018). A preliminary exploration of the barriers to delivering (and receiving) exposure-based cognitive behavioral therapy for anxiety disorders in adult community mental health settings. Community Mental Health Journal, 54(7), 899–911. https://doi.org/10.1007/s10597-018-0252-x
Keep Learning
- How might the findings of this review inform the development of individually tailored treatment programs for individuals with GAD?
- What are the potential implications of the review’s limitations, and how might future research address these limitations?
- Considering the evidence for the role of trait mindfulness in anxiety symptom reduction, how might clinicians effectively integrate mindfulness techniques into a predominantly CBT framework for treating GAD?
- What are the potential advantages and disadvantages of using manualised mindfulness programs versus ‘stand-alone’ mindfulness interventions for individuals with GAD?
- How might the additional benefits of mindfulness-based programs (e.g., changes in brain-circuitry and endocrine functioning) impact long-term outcomes for individuals with GAD, and what are the implications for relapse prevention?
