The effect of weighted blankets on sleep quality and mental health symptoms in people with psychiatric disorders in inpatient and outpatient settings: A systematic review and meta-analysis

There is limited synthesized evidence for weighted blankets usage in psychiatric patients. We performed a PRISMA compliant systematic review and meta-analysis of the effects of weighted blankets on sleep and mental health outcomes in psychiatric patients. MEDLINE, EMBASE, Cochrane Library, and PsycINFO were searched up to December 15th, 2023. Randomized controlled trials (RCT) or cohort studies reporting objective outcome scales of sleep and mental health were included. Standardized mean difference (SMD) measured effect size. Q and I² tests measured heterogeneity. Cochrane Risk of Bias Tool 2 and NIH Quality Assessment Tool assessed risk of bias. Nine studies of 553 psychiatric inpatients and outpatients with diagnoses including depression, bipolar disorder, ADHD, and autism. 289 participants received weighted blankets and 264 were in control groups. Intervention length ranged from 5 min to one year. Four studies reported evidence for weighted blankets in improving insomnia, total sleep time, and sleep onset latency. Six studies reported evidence for reducing anxiety symptoms. When compared to placebo, those using weighted blankets had improvements to anxiety symptoms (SMD = -0.47, 95% CI: -0.68 to -0.25, p < 0.001). One RCT had low risk of bias, 3 had some concerns, 1 was high risk. Three cohort studies were "fair" and one was "poor" in quality. It was found that weighted blankets can be effective in reducing anxiety in psychiatric patients. However, the literature is limited by heterogeneity of outcome reporting, lack of well designed RCTs, and small sample sizes. Highlighting the need for higher quality studies.