Reference
Ekholm B, Spulber S, Adler M. A randomized controlled study of weighted chain blankets for insomnia in psychiatric disorders. J Clin Sleep Med. 2020;16(9):1567-1577.
Study Objective
The aim of this study is to evaluate the use of weighted blankets to improve sleep in people with a variety of psychiatric illnesses.
Design
A randomized, controlled, blinded study in Stockholm County, Sweden
Participants
Study participants included 120 patients diagnosed with insomnia and 1 of several psychiatric disorders: major depressive disorder (38%), bipolar disorder (40%), generalized anxiety disorder (11%), or attention deficit hyperactivity disorder (11%). There was no effort to focus on 1 sex; however, 68% of participants were women. Average age was 40 years, with a range from 18 to 77. The average duration of insomnia was 20.2 years (SD 15.0). The majority of patients were on pharmaceutical treatment, and the researchers instructed them not to change their medications during the study. Medication use included: hypnotics (37%), sedatives (33%), lithium (20%), anticonvulsants (14%), antipsychotics (23%), antidepressants (53%), and stimulants (9%).
Intervention
Half of the participants were randomized to the weighted-blanket condition, which provided an 8-kg (17.6-lb) metal chain blanket. When participants initially were trying the blanket in the clinic, if they found it too heavy, they received a 6-kg (13.2-lb) blanket instead. The control blanket was comprised of plastic chain the same size and shape as the metal, giving a total weight of 1.535-kg (3.4-lb). One patient withdrew early, reporting an increase in anxiety with the weighted blanket. Researchers assessed insomnia severity after 4 weeks. At that point, the study became open for the following 12 months, with participants either continuing with the weighted blanket or switching to it if they had previously been in the control group. They had the opportunity to choose from 4 blankets (2 chain blankets at 6 or 8 kg, or 2 ball blankets at 6.5 or 7 kg). The majority (112 people) continued for the entire study, and the 7 who opted out were included in the final analysis.
Study Parameters Assessed
The primary outcome measure was sleep disturbance as assessed by the Insomnia Severity Index (ISI), which is a well-established self-report tool. The ISI has 7 items, which are summed and interpreted as ≤7 (meaning no insomnia), 8–14 (meaning subthreshold insomnia), 15–21 (moderately severe insomnia), and ≥22 (severe insomnia). Secondary measures focused on daytime symptoms and activity levels. These included actigraphy, the Fatigue Symptom Inventory, and the Hospital Anxiety and Depression Scale.
Key Findings
Researchers assessed participants for response and remission of their symptoms per the ISI score. The authors defined response as a decrease in ISI score of 50% or more from baseline, and remission as an ISI ≤7. At the initial assessment after 4 weeks of use, in the weighted blanket group, 59.4% had responded (vs 5.4% of the control group) and 42.2% were in remission (vs 3.6% of the control group). Over the 12-month continuation, the therapeutic effect increased, with 92% of all initial participants responding and 78% in remission. Objective measures using actigraphy did not show any significant effects on sleep parameters, though participants subjectively reported improved sleep maintenance. Remission of insomnia was 26 times greater with use of a weighted blanket than with the control blanket.
Deep pressure also increases oxytocin. Oxytocin promotes relaxation, a sense of security, and sleep.
Daytime functioning significantly improved in those using the weighted blankets. Subjectively the Fatigue Symptom Inventory was improved. Objectively, as captured by the actigraph, there was an overall increase in daytime activity, and the peak of activity was later in the day.
Further analysis compared responders (an ISI decrease of >50%) to nonresponders (<50% ISI decrease). Responders did have a significant improvement in subjectively reported sleep maintenance and a decrease in wakefulness after sleep onset on actigraphy. Daytime activity increased in both groups; however, the time delay in peak activity was significant only in responders. Participants using the weighted blankets had a significant decrease in depression and anxiety symptoms.
Practice Implications
Insomnia with comorbid psychiatric disorders is a common ailment found in primary care and in specialists’ clinics. An estimated 10% to 30% of adults have insomnia at any given time.1 What is especially concerning is that once a person experiences insomnia, it can persist for years. These disorders have a huge individual cost in lower quality of life, impaired daytime function, and personal expenses. The average insomnia treatment cost ranges from $200 to $1,200 per year, and employees with insomnia typically lose 11.3 days of work a year. The societal cost of insomnia is estimated at $63.2 billion per annum.2
The pharmaceutical management available for insomnia is less than ideal. Recent retrospective studies have shown increased risks of Alzheimer's disease and other types of cognitive decline associated with the long-term use of zolpidem, benzodiazepines, antipsychotics, and antidepressants.3 There is also the issue of lack of effectiveness. In 2017 the American Academy of Sleep Medicine (a section of the American Medical Association) found that the evidence for the use of hypnotics is “weak”4 and went on, in other publications, to suggest that cognitive behavioral therapy for insomnia (CBT-I) should be the first-line therapy for insomnia, and pharmaceuticals should only be used if CBT-I has failed, or in conjunction with CBT-I in severe or acute cases. Unfortunately, the availability of CBT-I practitioners is insufficient to address the large number of people suffering from insomnia.
Behavioral and other treatments for insomnia and for psychiatric disorders that have no side effects are ideal. In this study 1 patient reported feeling more anxious with the use of the weighted blanket. Notably, there were no other side effects reported.
Weighted blankets provide an even pressure to the whole body, with either metal chains or glass beads sewn between 2 layers of fabric. In the public media, they are generally recommended to be equivalent to 8% to 10% of the individuals’ body weight, or less. There are several suggested mechanisms of action for their effect on insomnia. First, they are thought to act similarly to massage by simulating touch. We know that people sleep better when they feel socially secure, and touch can be part of that. The deep pressure may stimulate parasympathetic action of the nervous system, while simultaneously downregulating sympathetic activation. Deep pressure also increases oxytocin. Oxytocin promotes relaxation, a sense of security, and sleep.5
The big question is, how universal is improvement in sleep with the use of a weighted blanket? This is not yet known, as there are few studies done to date. There have been several small studies looking at the use of weighted blankets by specific populations. A study of children with autism showed sleep was not improved. Children with attention deficit hyperactivity disorder had improved insomnia with the weighted blanket, and adults with chronic insomnia who were otherwise healthy improved. A recent review article, including 8 studies, concluded that although there is evidence for use of weighted blankets in treating anxiety, the evidence for use in insomnia is insufficient.6
So the question for now is: Can we recommend it to a wide range of people, some of whom also have comorbid diseases of different types? There are other considerations here. For one, the use of a weighted blanket is an intervention without reported or known side effects. Yet it is well established that ongoing insomnia contributes to many other health conditions—from hypertension to anxiety and depression. Insomnia also contributes to lower lifetime earnings and societal costs. The price of a weighted blanket is fairly minimal, and it is a treatment well accepted by patients. Therefore, at this time, we can recommend the use of weighted blankets for insomnia patients, while keeping an eye on the emerging literature.
