Acupuncture in circadian rhythm sleep-wake disorders and its potential neurochemical mechanisms

Circadian rhythm sleep-wake disorders are a growing problem in modern societies, particularly because of lifestyle changes including night-shift work, excessive exposure to artificial light, and irregular sleep schedules. These disorders affect not only sleep quality but also overall psychological and physical health. The exact prevalence is difficult to determine, but studies suggest it may range from 0.17% to as high as 8.9% of the adult population, depending on the specific disorder type and the population studied. Particularly concerning is the fact that many cases are not adequately diagnosed and are frequently mistaken for other forms of insomnia, which can lead to inappropriate treatment.

The primary aim of this study was to review and analyze the effectiveness of acupuncture in the treatment of circadian sleep disorders, as well as to understand the underlying neurobiochemical mechanisms. The investigators used a comprehensive literature review methodology, searching for randomized controlled clinical trials and experimental animal studies in major medical databases including PubMed, Web of Science, and Chinese-language databases. The analysis included both studies evaluating the clinical efficacy of acupuncture and investigations of its mechanisms of action at the level of central and peripheral biological clocks. Inclusion criteria were rigorous, focusing specifically on standardized circadian disorders and traditional acupuncture interventions, while excluding case reports and reviews to ensure the quality of the evidence analyzed.

The results demonstrated that acupuncture can effectively modulate disrupted circadian rhythms through multiple neurobiochemical mechanisms. Animal studies showed that acupuncture can regulate the expression of circadian clock genes, including Clock, Bmal1, Per1, and Per2, both in the suprachiasmatic nucleus, which acts as the body's central pacemaker, and in peripheral tissues such as the liver and heart. The therapy also demonstrated the ability to modulate key neurotransmitters involved in sleep regulation, including serotonin, norepinephrine, dopamine, and gamma-aminobutyric acid, and to influence levels of melatonin, the hormone fundamental to sleep-cycle regulation. Clinical studies confirmed significant improvements in sleep-quality scales, reduced sleep latency, increased sleep efficiency, and decreased daytime symptoms such as drowsiness and fatigue.

Frequently used acupuncture points included HT-7, PC-6, SP-6, and GV-20 among others, with different point combinations showing synergistic effects in treatment.

For patients and clinicians, these findings suggest that acupuncture represents a promising and safe therapeutic alternative for the treatment of circadian sleep disorders. Unlike conventional medications such as benzodiazepines and antidepressants, which can cause dependence and significant adverse effects, acupuncture demonstrated an excellent safety profile with minimal risks when administered by qualified practitioners. The therapy proved particularly effective for associated symptoms such as anxiety, depression, and fatigue, which frequently accompany sleep disorders. The temporal characteristic of acupuncture is especially relevant, as different times of administration may have distinct effects on circadian rhythm regulation, allowing for more personalized and targeted treatment.

For clinicians, this means acupuncture can be integrated as part of a comprehensive therapeutic approach, especially for patients who do not respond well to conventional pharmacologic treatments or who prefer more natural treatment options.

Despite the promising results, the study acknowledges several important limitations that must be considered. Many of the analyzed studies were conducted in animal models, which may limit direct applicability to humans, given that sleep patterns differ substantially between rodents and humans. The lack of standardization in acupuncture protocols, including point selection, manipulation techniques, treatment duration, and frequency, makes it difficult to establish definitive therapeutic guidelines. Some clinical studies showed inconsistent results when comparing real with sham acupuncture, possibly because of acupressure effects or methodological variations.

Furthermore, evaluating the effectiveness of acupuncture in circadian disorders is particularly challenging, as it requires extended observation periods and rigorous control of other factors influencing circadian rhythms, such as light exposure and meal timing. The investigators suggest that future research should focus on developing standardized protocols, using objective sleep-assessment methods such as polysomnography and actigraphy, and conducting more long-term randomized controlled trials to definitively establish the efficacy and mechanisms of action of acupuncture in the treatment of circadian sleep disorders.