Safety and effectiveness of weighted blankets for symptom management in patients with mental disorders: A systematic review and meta-analysis of randomized controlled trials

Background

The current practice guideline regarding treatment for insomnia and sleep disturbances among children and adolescents with autism spectrum disorder (ASD) has been published and it suggests that the use of weighted blankets might not be an evidence-informed practice. However, limited guidance and evidence synthesis exist on the overall effectiveness of a weighted blanket for symptom management among patients with mental disorders, although it has been routinely recommended and prescribed for this population in many mental health care settings.

Objective

To systematically evaluate and synthesize existing data on the safety and effectiveness of weighted blankets for symptom management among patients with mental disorders.

Methods

Comprehensive retrieval of published, unpublished, or ongoing studies was carried out across a series of bibliographic databases, grey literature sources, and clinical trial registry platforms, along with manual screening of the reference lists of the included studies or relevant reviews. Randomized controlled trials (RCTs) were included if they compared a weighted blanket intervention and a control condition among patients with mental disorders. Two reviewers independently extracted the data using a pre-specified form and assessed the methodological quality of the included studies with the revised Cochrane ‘Risk of Bias’ (RoB 2) tool. Review Manager (RevMan) 5.3 software was used to conduct the meta-analysis when possible. Subgroup and sensitivity analyses, where appropriate, were conducted to explore the robustness of the pooled effect estimates.

Results

Eight studies involving a total of 426 patients were included in this review. Half of the included studies were rated as having a high risk of bias, primarily due to the failure to blind participants for participant-reported measures. No serious adverse events were reported with the application of weighted blankets. The meta-analysis of five studies revealed that the use of weighted blankets induced a small magnitude decrease (standardized mean difference within studies [SMD]= 0.40) in anxiety management. The pooled estimate of three studies reporting the effect of weighted blankets on insomnia revealed a nonsignificant difference between the two groups (mean difference [MD] = −1.92, 95 % confidence interval [CI] = −3.92–0.09, p = 0.06). However, the leave-one-out sensitivity analysis of the two remaining homogeneous studies revealed that patients who used weighted blankets had reduced insomnia severity index (ISI) scores (MD = −2.78, 95 % CI = −4.44 to −1.12, p = 0.001). Additionally, a study without available data for inclusion in the meta-analysis also reported a positive effect in reducing the ISI score. Due to the heterogeneity across studies, summary estimates for the effects of weighted blankets on fatigue and depression were not computed. However, primary studies reporting these two outcomes demonstrated that the application of weighted blankets had a positive effect.

Conclusion

Weighted blankets may be a safe and effective add-on treatment for managing common symptoms such as anxiety, insomnia, depression, and fatigue among psychiatric patients. However, these results need to be further confirmed due to the limited number of studies included in this review, the small sample size and the significant heterogeneity across these primary studies. To gain a better understanding of the effect and mechanism of weight blankets, future trials should preferably integrate more objective measures.