Insomnia is prevalent among adults, particularly in those who have comorbid psychiatric diagnoses. About 40% of people with insomnia do not respond to standard treatment, such as cognitive behavioral or pharmacological therapies. A controlled study was designed to evaluate the effect of weighted chain blankets, which provide a form of deep-pressure stimulation, on insomnia and daytime sleep-related symptoms in patients with major depressive disorder, bipolar disorder, generalized anxiety disorder, or attention deficit-hyperactivity disorder.

A total of 120 patients who had problematic insomnia were recruited from affective disorder clinics and randomly assigned a weighted chain blanket or a control blanket.

Compared with the control blanket, use of the weighted blanket had a significant effect on Insomnia Severity Index ratings, the primary outcome measure, in all participants. This became apparent after one week. In the weighted blanket group, the response rate was 59.4% compared with 5.4% in the control blanket group. The remission rate was 42.2% and 3.6%, respectively. The likelihood of responding was almost 26 times higher and the likelihood of remission nearly 20 times higher in the weighted blanket group compared with the control blanket group. Patients who switched from the control blanket to the weighted blanket had an effect similar to those who had used the weighted blanket from the beginning, and improvements increased during the 12 months of follow-up.

Patients who used weighted blankets also had less daytime fatigue, a higher daytime activity level, better sleep maintenance, and significantly decreased symptoms of depression and anxiety.

One limitation of the study was the risk that the type of blanket might be disclosed to the rater, who was supposed to be blind to treatment allocation. Another was that the objective evaluation of sleep was limited, because sleep journals and polysomnographic recordings weren't used.