The blankets have a long history of use in a type of occupational therapy called sensory integration therapy. This treatment is sometimes used to help people with autism or other disorders to focus on sensory experiences, which experts say may boost these individuals' ability to regulate their emotions and behavior. Weighted blankets are one tool therapists use to provide "deep-touch pressure," May-Benson said.
The idea behind deep-pressure touch is that it stimulates the release of serotonin and dopamine, two neurotransmitters that tend to make people feel more relaxed. Some research suggests that slow and gentle touch can stimulate portions of the limbic system, the brain's network for processing emotion and fear. Many people with sensory-processing disorders are hypersensitive to touch, May-Benson said, and deep pressure can help desensitize and calm them.
Four studies have focused on weighted blankets. In the earliest of those studies, published in 2008 in the journal Occupational Therapy in Mental Health, researchers asked 33 adults to rest under 30-lb. (13.6 kg) blankets for 5 minutes. They found that 33 percent showed a greater drop in skin conductance — a measure of arousal that is based on minuscule differences in the amount of sweat on the skin — with a weighted blanket than without. Nineteen participants said they felt more relaxed with the blanket.
In the another study, published in 2016 in the Journal of the Formosan Medical Association, researchers suggested that the blankets may help people in stressful circumstances. The researchers found that the study participants who wore a weighted blanket during wisdom tooth extraction showed enhanced activity in the branch of the nervous system that takes over in times of low stress.
The results suggest that "deep-pressure input may be an appropriate therapeutic modality" for people in stressful conditions, the researchers concluded.