This is a really interesting study on the “Effects of Laughter Therapy on Depression and Sleep among Patients at Long-term Care Hospitals” undertaken in 2017 by the Korean Society of Adult Nursing.
Full details can be found in the link below:
“This study showed that laughter therapy with more intense physical activities reduced depression and improved sleep among the participants in the LTC hospitals. To improve depression and sleep quality in older adults, laughter therapy strengthening physical activities might be beneficial if it can be offered more than two times a week. The findings of this study suggest that laughter therapy must enhance more physical activities to improve depression and sleep.”