by Vladimir Hedrih

(Photo credit: Adobe Stock).

A meta-analysis of studies examining the effects of qigong, tai chi, and yoga-based interventions on symptoms of anxiety and depression found that yoga-based interventions were effective in decreasing these symptoms. Tai chi and qigong had no effect on depression symptoms. The authors of the study reported a high risk of bias in the analyzed studies. The study was published in the British Journal of Sports Medicine.

Affective disorders such as anxiety and depression affect a large share of the population. It is estimated that approximately 20% suffer from depression, while anxiety disorders affect between 4% and 25% of people worldwide. These disorders frequently present chronic symptoms, leading to disability and substantial socioeconomic costs.

Treatments for affective disorders are sometimes less effective than desired, leading health professionals to seek ways to enhance existing treatments. Exercise has emerged as a promising avenue in this respect. Several studies suggest that exercise can improve symptoms of affective disorders, either as an adjunct therapy or as a standalone treatment. Numerous empirical studies have explored the effects of mind-body practices like qigong, tai chi, and yoga on these disorders, often reporting mental health improvements following such interventions.

Qigong is a Chinese mind-body practice involving coordinated movements, breath control, and meditation to cultivate and balance the body’s vital energy or “qi” for improved physical and mental well-being. Tai Chi originates from Chinese martial arts. It is a meditative and slow-paced exercise characterized by flowing, graceful movements, promoting balance, flexibility, and relaxation while fostering a connection between mind and body. Yoga is an ancient Indian practice that combines physical postures, breath control, meditation, and ethical principles to enhance physical and mental health, promoting unity of the body, mind, and spirit.

Study author Javier Martínez-Calderon and his colleagues wanted to synthesize the results of studies evaluating effects of interventions based on these three types of practice on symptoms of depression and anxiety. They also wanted to identify factors that might modulate their effectiveness.

The researchers conducted a search through scientific journal databases for articles presenting the results of randomized clinical trials. These trials investigated the effectiveness of qigong, tai chi, and yoga in alleviating anxiety and depression symptoms in adults clinically diagnosed with these disorders.

The search resulted in 22 studies presented in 23 different papers. These were selected out of a wider body of 305 publications that matched search criteria, but did not fulfill all the conditions to be included in the meta-analysis. Independent reviewers were employed by the study authors to evaluate the risk of bias, the certainty of evidence, the adequacy of procedural descriptions, and the presence of information spin in the paper summaries.

In total, these studies encompassed 1,420 participants. Two clinical trials specifically evaluated yoga-based interventions for anxiety disorder symptoms, comparing the effects of yoga with drug therapy or naturopathy (lifestyle modification or prevention), with intervention durations ranging from 3 to 12 weeks. The rest of the studies concentrated on depression: 16 investigating yoga, four examining tai chi, and two assessing the effects of qigong. These studies compared the impact of these exercises on depression against usual care, waitlists, education, drug therapy, aerobic exercise, or psychotherapy.

The reviewers determined that all these studies had a significant risk of bias. Except for one, the summaries of all studies exhibited some form of information spin, potentially indicating a degree of misrepresentation in study findings. The most prevalent form of spin involved not mentioning the adverse effects of interventions and selectively reporting positive results while omitting negative ones. Notably, no paper provided complete details of the interventions used. The reviewers assessed the certainty of evidence for all outcomes as low.

The meta-analysis revealed that in the two studies focusing on individuals with anxiety disorders, yoga-based interventions were more effective than control measures in reducing anxiety symptoms. However, in studies involving individuals with depressive disorders, yoga-based interventions did not outperform controls in lessening anxiety.

Initial analysis of effects of yoga-based interventions on depressive symptoms of individuals suffering from depression also found no effect. However, researchers noted that the yoga-based interventions applied were very heterogenous. After excluding three studies, the remaining studies showed that yoga-based interventions were better than controls in reducing depression symptoms. Statistical analyses showed no effects of qigong or tai chi interventions on depressive symptoms.

“We observed that yoga-based interventions may reduce anxiety symptoms in anxiety disorders. Furthermore, we also found that yoga-based interventions may decrease depression symptoms in depressive disorders. However, we cannot make definitive clinical recommendations due to the very low certainty of the evidence, several methodological concerns and the heterogeneity of qigong, tai chi and yoga styles among studies. Therefore, a specific yoga style cannot be recommended with the current evidence,” the study authors concluded.

The study makes a valuable contribution to the systematization of knowledge about effects of exercise on mental health. However, as authors of the study already noted themselves, the methodological quality of the studies analyzed in this meta-analysis and papers their results were reported in was very low. Therefore, these findings should be approached with caution.

The paper, “Yoga-based interventions may reduce anxiety symptoms in anxiety disorders and depression symptoms in depressive disorders: a systematic review with meta-analysis and meta-regression”, was authored by Javier Martínez-Calderon, María Jesús Casuso-Holgado, Maria Jesus Muñoz-Fernandez, Cristina Garcia-Muñoz, and Alberto Marcos Heredia-Rizo.