Controlled Study of Chain Blanket for Insomnia

The aim of the study is to compare an intervention with a weighted metal chain blanket of 8 kg with a control plastic chain blanket of 1,5 kg for patients with Major depressive disorder, bipolar disorder, Generalized Anxiety Disorder (GAD) and/or attention deficit hyperactivity disorder (ADHD) and co-occurring insomnia. Patients are evaluated by a rater blind to treatment allocation with Insomnia Severity Index (ISI), Fatigue Symptom Inventory (FSI), Hospital Anxiety and Depression Scale (HAD) and actigraphy before, during and at primary end-point after 4 weeks use of the blanket.

Insomnia is a common and problematic symptom in many psychiatric disorders. The aim of this study is to evaluate the effect of weighted chain blankets on insomnia and other sleep-related symptoms for patients with Major depressive disorder, Bipolar disorder, Generalized Anxiety Disorder (GAD) and/or ADHD. Potential participants are asked to participate in a study comparing two different types of chain blankets, not mentioning the difference in weight. After signing a informed consent, participants were randomly assigned on a 50/50 basis to a weighted blanket containing metal chains weighing 8 kg or a control blanket containing plastic chains weighing 1,5 kg. Insomnia severity is assessed before and weekly until endpoint at four weeks use of the blanket by a rater blind to treatment allocation. Participants sleep will also be monitored by actigraphy. The controlled phase of the study is followed by a one year open follow up study where all participants are offered to use a weighted blanket of any type.

Study participants were kept blind to treatment allocation by the information that they would be assigned to one of two types of chain blanket, without any information of the difference in weight. The outcome assessor and investigator did not participate in randomization and treatment and were blind to treatment allocation.

As experimental intervention, a weighted metal chain blanket of 8 kg was used during the night. Using a flexible dose protocol, participants who found the 8 kg blanket too heavy were allowed to change to a 6 kg weighted blanket (see below)

As sham comparator, light chain blankets were used, were plastic chains of the same shape and size as the metal chains in the weighted blanket were sewn in. The control blanket has a weight of 1535 grams. When checking the weight of standard blankets for sale in one of the largest stores in Stockholm, weight was ranging from 550 to 2389 grams (average 1332).

Self-report rating scale assessing the severity of insomnia symptoms. Range 0-28 with higher scores indicating a more severe insomnia

Self-report symptom rating scale for daytime fatigue symptoms. Range 0-130 with higher scores indicating a more severe fatigue.

An actigraph attached to the arm of the participants on the week before the intervention and during the fourth (last) week of the intervention assessing sleep by interpretation of movement

"Day and night diaries", developed by Assistive technology Stockholm for the evaluation of weighted blankets

Change from start to 4 weeks use of the blanket in patient estimated time (minutes) from going to bed to sleep onset.

HAD is a self report rating scale for anxiety and depression symptoms.The HAD is subdivided into subscales for depressive symptoms (HAD-D) and anxiety symptoms (HAD-A), with a range of 0-21 for each subscale. Higher scores indicates more severe symptoms.

Self-report rating scale assessing the severity of insomnia symptoms. Range 0-28 with higher scores indicating a more severe insomnia

Inclusion Criteria: • Clinical insomnia for more than two months with a score over 14 points at the Insomnia Severity Index (ISI)1 and a diagnosis of either major depressive disorder, bipolar disorder, Generalized Anxiety disorder (GAD) or ADHD. Exclusion Criteria: active drug abuse, overuse of sleep medication, illness affecting cognitive functions, such as dementia, schizophrenia, developmental disorders, Parkinson's disease or an acquired brain injury.

Ekholm B, Spulber S, Adler M. A randomized controlled study of weighted chain blankets for insomnia in psychiatric disorders. J Clin Sleep Med. 2020 Sep 15;16(9):1567-1577. doi: 10.5664/jcsm.8636.