Complementary and Alternative Medicine for the Treatment of Insomnia: An Overview of Scientific Evidence from 2008 to 2018

Insomnia is a widespread sleep disorder in the general population, and it is a risk factor for impaired function, the development of other medical and mental disorders, and causes an increase in health care costs. In view of the health hazards of insomnia and the shortcomings of western medicine, Complementary and Alternative Medicine (CAM) should be considered in the management of insomnia. The present overview reports the potential role of herbal medicine and non-pharmacological therapies in the treatment of insomnia and summarizes the scientific evidence reported from 2008 to 2018. PubMed and Web of Science databases were searched for studies published from 2008 to 2018. 17 randomized controlled trials and 22 non-pharmacological therapies were included in this review, and the results showed that CAM had certain advantages in the treatment of insomnia. The safety of CAM for insomnia was acceptable. Meanwhile, based on pre-clinical trial, the possible mechanisms of CAM for insomnia were modulation of circadian rhythm, GABA receptor activation, antagonisms of 5-HT receptors, inhibition of glutamate-mediated pathways, and attenuation of inflammation. CAM for insomnia has made some progress, but high quality evidence-based medical evidence is still needed to provide guidance for clinical application.