The effect of non-pharmacological interventions on sleep quality in people with sleep disturbances: A systematic review and a meta-analysis

Sleep is the elixir of life. Both healthy populations and patients with chronic diseases experience sleep disturbances in their lifetime. Pharmacological agents to induce sleep in individuals with sleep disturbances pose side effects like tolerance and dependence, warranting the development of alternative non-pharmacological interventions with less or no adverse effects. However, deciphering comprehensive evidence on the translational potential of these alternative therapies remains difficult. In the current paper, we systematically reviewed the recent literature on the effect of non-pharmacological interventions (NPIs) on improving sleep quality in both healthy and diseased populations experiencing sleep disturbances. We searched PubMed, Science Direct, Cochrane Controlled Trials, and Web of Science databases from inception to June 2022 for randomized controlled trials and cohort studies evaluating the sleep quality of individuals. We performed a meta-analysis using the random effects model with Pittsburgh Sleep Quality Index (PSQI) as an outcome measure to evaluate the effect of five distinct NPIs on sleep quality in normal and people with different medical conditions. Subgroup analyses and sensitivity analyses were done for heterogeneity analysis and to check the consistency of results, respectively. In 16 trials reporting on 1885 subjects, that all NPIs like Resistance Training (SMD -0.29, 95% CI -0.64 to 0.05; p = 0.09); Yoga (SMD -0.48, 95% CI -0.72 to -0.25; p < 0.0001); Cognitive Behavioral Therapy (SMD -1.69, 95% CI -2.70 to -0.68; p = 0.001); Music (SMD -1.42, 95% CI -1.99 to -0.85; p < 0.00001); Light (SMD -0.43, 95% CI -0.77 to -0.09; p = 0.01) have substantially decreased the global PSQI scores. The findings of the randomized studies and a cohort study included in qualitative synthesis demonstrated that the global PSQI scores improved significantly as compared to the placebo groups. Despite the limitations of clinical heterogeneity in subjects, our results demonstrate a positive impact of the studied NPIs on sleep quality in individuals experiencing sleep disturbances. However, comprehensive double-blinded controlled trials are indispensable in the future, emphasizing the objective sleep quality and inter-individual differences in response to the intervention.