In a recent systematic review and network meta-analysis published in the British Medical Journal, researchers determined the potentially most effective exercise regimen and dosage in managing major depressive disorder (MDD) in comparison to antidepressants, psychotherapy, and control interventions.
Study: Effect of exercise for depression: systematic review and network meta-analysis of randomised controlled trials. Image Credit: Dmytrenko Vlad/Shutterstock.com
They found that exercise, in the form of yoga, walking, jogging, or strength training, is an effective and well-tolerated treatment for depression, suggesting its potential as a core intervention alongside antidepressants and psychotherapy, regardless of comorbidities or baseline depression levels.
Background
MDD is a leading global cause of disability, impacting life satisfaction significantly and exacerbating comorbidities. Despite the availability of treatments, the potential resistance and limited access to them emphasize the urgent need for evidence-based interventions. Although exercise is suggested as a potential adjunct or alternative to traditional treatments for depression, backed by international guidelines, the recommendations on dose and modality vary across regions. Guidelines suggest diverse approaches, including group exercise programs, aerobic or resistance training, or a combination of both.
Existing pairwise meta-analyses assessing specific exercise modalities versus comparators face challenges due to heterogeneous treatments and comparisons, leading to ambiguous effect estimates. Overviews of reviews have attempted to address this by combining pairwise meta-analyses, but differences in analytical methods can still lead to confusion.
In this regard, network meta-analyses may offer a more precise approach by simultaneously modeling direct and indirect comparisons between interventions. Previous network meta-analyses have examined the effects of exercise on various outcomes, including depression, but may have been underpowered to explore moderators such as dose and modality.
To address this gap, researchers in the present study conducted a comprehensive search of randomized trials to identify the optimal dose and modality of exercise for depression, considering factors like participants’ sex, age, and baseline depression level. To enhance the intervention effects for depression, they investigated autonomy support and behavior change techniques, examining their associations with intervention outcomes. Additionally, they explored intervention mechanisms, including self-confidence and affect, through formal mediation analyses in the included studies.
About the studyTop of Form
In the present study, randomized controlled trials investigating exercise as a treatment for depression were included, with participants meeting the criteria for MDD, either clinically diagnosed or self-reported to exceed established clinical thresholds. Data were sourced from Medline, Embase, Cochrane Library, SPORTDiscus, and PsycINFO databases. Studies were eligible whether all participants or only a subgroup had depression.
Studies with various comparison conditions, participant profiles, and languages were considered, aiming to evaluate exercise’s efficacy in depression treatment comprehensively. Exclusion criteria were interventions shorter than a week, insufficient depression outcome data, and inability to calculate effect sizes. A total of 218 studies were included, with 495 arms and 14,170 participants.
For each study, intervention details, including exercise frequency, intensity, type, and duration, were assessed alongside behavior change techniques, level of autonomy, comparison conditions, and participant characteristics. The energy expenditure dose of exercise was determined for each arm in the form of metabolic equivalents of task (METs) min/week.
The risk of bias in the included studies was assessed using Cochrane’s tool. Bayesian arm-based multilevel network meta-analysis models were employed for main and moderation analyses, using standardized mean change from baseline as the summary measure. Active control conditions were grouped together (such as usual care and placebo tablet), while waitlist control was considered separately due to its typically poorer effects. Netmeta and CINeMA were used for assessing credibility and modeling acceptability. Prespecified moderation and sensitivity analyses were performed to assess the robustness of the findings.
Results and discussion
Compared to active controls, dance showed large reductions in depression (Hedges’ g -0.96), followed by moderate reductions for walking or jogging (g -0.63), yoga (g -0.55), strength training (g -0.49), mixed aerobic exercises (g -0.43), and tai chi or qigong (g -0.42). Moderate effects were also seen on combining exercise with SSRIs (short for selective serotonin reuptake inhibitor, g -0.55) or combining aerobic exercise with psychotherapy (g -0.54).
These treatments outperformed the clinically important difference threshold (g -0.20). Strength training and yoga had lower dropout rates compared to active controls and were perceived as the most acceptable options. Effects were moderate for cognitive behavior therapy alone (g -0.55) and small for SSRIs (g -0.26). However, while the publication bias was found to be low, only one study met the criteria for low risk of bias.
Although the review provides insights into the potential of dance for the treatment of depression, the small number of studies, bias in study designs, and lack of blinding in interventions limit the strength of the overall recommendations.
Conclusion
In conclusion, as per the study, exercises including walking, strength training, and yoga show promise as a treatment for depression, although the confidence in the findings may vary. In the future, tailoring exercise-based interventions to suit individual characteristics and combining them as core treatment along with antidepressants and psychotherapy may improve the outcomes for patients with MDD, offering accessible options, particularly for those with barriers to participation.
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