Sleep disorders are common among persons with dementia: 50.8% of them have insomnia. 1 The behavioural and psychological symptoms of dementia (BPSD), including day‐night reversal and wandering during the night, increase the care burden of patients' family members and care staff. In general, pharmacological therapy is prescribed to treat sleep disorders; however, as its effectiveness is limited, non‐pharmacological therapy (NPT) has also been proposed. 2 Weighted blankets (WBs) have been used as an NPT in the USA and the Nordic countries, and their effectiveness has started to attract the attention of Japanese medical professionals. Phototherapy is the most common and effective form of NPT, and other forms of this intervention such as lifestyle therapy, electrical stimulation, and cognitive behavioural therapy are also widely employed. 3 To facilitate better sleep quality in persons with dementia afflicted with symptoms of day‐night reversal, the Alzheimer's Association of America recommends various types of lifestyle changes: reducing naps, increasing daytime activity, and regulating sleep rhythms with adequate exposure to sunlight. 4 WBs have demonstrated positive psychological effects in adults with depression and in children with developmental disabilities. They have also been used for persons with dementia in Nordic countries. Field et al. reported that pressure stimulation of the body releases oxytocin, a happy hormone, which has a calming effect and activates the secretion of serotonin. 5 This study was the first clinical trial of WBs for persons with dementia in Japan. CASE PRESENTATION Our case study demonstrates the effectiveness of a WB for a person with severe dementia. The participant was a woman in her 80s living in a nursing home who agreed to participate in the study. At the time of the case study, she was 138 cm tall and weighed 42 kg. She was diagnosed with Alzheimer's disease in 1991. Her symptoms progressed over time, and she began to exhibit symptoms such as wandering, collecting things, and odd eating behaviours. There were complaints from the neighbours about these symptoms, and she was moved to a nursing home in June 2016. At that time, her Clinical Dementia Rating was 3 (severe dementia) and ranked at care level 5 (extreme need of care) on the Long‐term Care Insurance system. She had a sleep disorder, with BPSD including day‐night reversal, wandering during the night, and hallucinations. Because she had difficulty answering questions, using the Mini‐Mental State Examination was not feasible. She had never received pharmacological therapy for her sleep disorder, and her only daily medication was a laxative. She needed mild care support with daily activities. For example, when she fell asleep while sitting up and eating, the care staff would help her eat. She frequently left her room and wandered around the floor throughout the night. The care staff would catch her wandering and lead her back to bed to lie down. The care staff attempted lifestyle therapies from the time of her admission, such as promoting participation in activities during the day and sleep induction at night. The results of the lifestyle therapies showed a slight increase in sleep time, but her nocturnal auditory hallucinations, hallucinations, and wandering did not decrease; thus, the burden on the care staff increased.