Lifestyle medicine for depression: A meta-analysis of randomized controlled trials

Highlights

• The pathogenesis and progression of depression may depend on different lifestyle determinants related to depression.

• The lifestyle medicine approach may be of great potential to be implemented as an entry-level community intervention to prevent depression and an adjunctive intervention in managing major depression.

• The number of lifestyle factors adopted was a significant moderator for the effect of multi-component lifestyle medicine interventions on depression.

• The clinical effect of multi-component lifestyle interventions tend to be stronger in major depression.

• Smartphone-delivered lifestyle medicine interventions are needed to increase accessibility and support intervention compliance.

Abstract

Background

The treatment effect of multi-component LM interventions on depressive symptoms has not yet been examined.

Methods

We systematically searched six databases from inception to February 2020 to identify randomized controlled trials (RCTs) involving any multi-component LM interventions (physical activity, nutritional advice, sleep management, and/or stress management) on depressive symptoms relative to care as usual (CAU), waitlist (WL), no intervention (NI), or attention control (AC) comparisons.

Results

Fifty studies with 8,479 participants were included. Multi-component LM interventions reduced depressive symptoms significantly relative to the CAU (p >.001; d = 0.20) and WL/NI (p > .01; d = 0.22) comparisons at immediate posttreatment. However, no significant difference was found when compared with AC. The intervention effects were maintained in the short-term (1- to 3-month follow-up) relative to the CAU comparison (p > .05; d = 0.25), but not in the medium- and long-term. The moderator analyses examining the effect of multi-component LM interventions compared with CAU suggested that the number of lifestyle factors adopted was a significant moderator. Although disease type was not a significant moderator, there was a tendency that the clinical effect of multi-component LM interventions was stronger (d = 0.45) in those diagnosed with major depression. No publication bias was detected.

Limitations

Low number of RCTs available in some subgroup analyses prevented from finding meaningful effects. Results may not be extended to major depression, because data on secondary depression were captured.

Conclusion

Multi-component LM interventions appeared to be effective in mitigating depressive symptoms; however, the magnitude of the clinical effect was small. Future research is needed to assess more comprehensive and individualized LM interventions which have a greater emphasis on motivational and compliance aspects and focus solely on individuals with depression.

Introduction

Depression is a debilitating mental health condition that is primarily characterized by persistent depressed mood and loss of interest or pleasure in usual activities (American Psychiatric Association, 2013). Despite effective treatments for depression are present, the prevalence of depression has been increasing in recent decades (World Health Organization, 2017). Previous reviews suggested that the rise was in part potentially influenced by changes in lifestyle related to modernity in the past few decades (Sarris et al., 2014). Apart from biochemical, genetic, and psychological factors, there is compelling evidence indicating that a cascade of unhealthy lifestyle behaviors, such as physical inactivity, pro-inflammatory nutrients rich diet, sleep disturbance, may be in part related to the increased risk of depression (Kraus et al., 2019; Park et al., 2019; Sarris et al., 2014). Specifically, a meta-analysis of 25 randomized controlled trials (RCTs; n = 1487) showed that exercise has large antidepressant effects on depression, including major depressive disorder (MDD) (Schuch et al., 2016). Moreover, studies also demonstrated that the effects of exercise as treatment for mild to moderate depression is comparable to first-line treatments, such as medications and cognitive-behavioral therapy (CBT) (Carek et al., 2011; Cooney et al., 2013; Kvam et al., 2016). Altering dietary patterns can contribute to the development and trajectory of depression. A recent meta-analysis of 16 RCTs (n = 45,826) strongly suggested that diet interventions play a role in the management of depressive symptoms across the population (Firth et al., 2019). In terms of sleep disturbance, previous studies found that sleep disturbance in depression is common with more than 80 percent depressed individuals suffering from insomnia (Armitage, 2007; Soehner et al., 2014; Steiger and Pawlowski, 2019). Sleep disturbance has been suggested as a biologically and theoretically plausible transdiagnostic contributor to depression (Harvey, 2008; Harvey et al., 2011). A meta-analytic review which included 21 longitudinal epidemiological studies found that non-depressed individuals with insomnia have a twofold increase in the risk for depression (Baglioni et al., 2011).

The aforementioned evidence demonstrated that the pathogenesis and progression of depression may depend on different lifestyle determinants related to depression. It is therefore imperative to adopt the multifaceted approach by considering the modifiable underlying lifestyle determinants to manage depression. One approach that has been gaining increasing popularity for managing diseases with a lifestyle etiology is lifestyle medicine (LM) (Egger et al., 2009). LM is the adoption of a multi-component approach, involving combinations of nutrition, physical activity, sleep and stress management as a therapeutic modality (Egger et al., 2009; Ripoll, 2012; The American College of Lifestyle Medicine, 2019). LM is ideally applied as a comprehensive, multifaceted approach that considers several levels of causality of a given disease and focuses on both prevention and therapeutic management. A recently published meta-analytic review has evaluated the preventive effect of universal multi-component LM interventions in improving depressive symptoms (Gómez-Gómez et al., 2020). The review pooled 20 RCTs which employed nutrition, physical activity, and/or smoking cessation as LM interventions. The findings revealed that LM interventions had a small preventive effect on depressive symptoms in non-clinically depressed adults relative to a care as usual/waitlist/no intervention/attention control (CAU/WL/NI/AC) comparison. However, because of high heterogeneity and generally low study quality, the authors concluded that there was insufficient evidence to conclude the effect of universal multi-component LM interventions in reducing depressive symptoms. Moreover, their review has intentionally excluded the clinically depressed population to study the preventive effect of LM intervention on depressive symptoms. Given multi-component LM interventions could potentially be applied as a practice for managing clinical depression, the examination of multi-component LM interventions for clinical depression is thus warranted. Additionally, the limited inclusion of lifestyle factors (i.e., nutrition, physical activity, and smoking cessation) in their review may restrict the effect size observed; therefore, other strong determinants of depression should be considered in multi-component LM interventions. Besides, the durability of treatment effects of multi-component LM interventions on depression remained unknown in the current literature, albeit long-term involvement was emphasized in the LM approach (Egger et al., 2009; Ripoll, 2012).

Taken together, there is a need for a more comprehensive meta-analysis which considers not only the preventive effects of multi-component LM interventions for depression, but also the treatment effects of a range of strong lifestyle factors that are strongly associated with the pathogenesis and progression of depression. This meta-analytic review aimed to examine the effect of multi-component LM interventions in reducing depressive symptoms relative to a CAU, WL/NI, and AC comparison. Potential moderators for the effect of multi-component LM intervention on depressive symptoms were explored.