Efficacy and Safety of Scalp Acupuncture for Insomnia: A Systematic Review and Meta-Analysis

Insomnia is a problem that affects millions of people worldwide, interfering with quality of life and daily functioning. In Brazil, about 31% of the population suffers from some degree of insomnia, while the worldwide average is around 27%. This sleep disorder not only impairs nighttime rest but can also increase the risk of developing other diseases, causing significant psychological and economic impact for both patients and their families. With the increase in pace of life and social pressures, the search for effective and safe treatments for insomnia has become increasingly urgent.

Although medications are widely used to treat insomnia, their side effects and potential for dependence lead many people to seek therapeutic alternatives.

Within this context, scalp acupuncture, also known as cranial acupuncture, emerges as a promising therapeutic modality. This technique differs from traditional body acupuncture by stimulating specific points on the head, taking advantage of proximity to the cerebral cortex to directly influence functional areas of the brain related to sleep. Scalp acupuncture combines the benefits of traditional Chinese medicine with the advantage of being a non-pharmacologic intervention, potentially free from the adverse effects associated with conventional pharmacologic treatments.

This study aimed to systematically evaluate the efficacy and safety of scalp acupuncture in the treatment of insomnia through a systematic review and meta-analysis. The researchers conducted a comprehensive search in seven scientific databases, including Chinese and international repositories, from the establishment of these databases through July 2020. Inclusion criteria were rigorously defined: only randomized controlled trials were considered, involving patients with a confirmed diagnosis of insomnia, where the treatment group received scalp acupuncture exclusively. Control groups varied between conventional insomnia medications, other forms of acupuncture, or no treatment.

Outcomes analyzed included treatment efficacy rate, score on the Pittsburgh Sleep Quality Index (PSQI), and occurrence of adverse events. Two independent researchers performed study selection, data extraction, and quality assessment, using standardized tools for statistical analysis.

The final analysis included 21 studies involving 1,606 patients, with 804 in the scalp acupuncture group and 802 in the control groups. The results demonstrated significant benefits of scalp acupuncture compared with conventional treatments. In the analysis of efficacy rate, scalp acupuncture showed superior results, with an odds ratio of 2.73 and a highly significant confidence interval. When compared specifically with medications and no treatment, scalp acupuncture showed substantial improvements in PSQI scores, indicating better sleep quality.

Interestingly, when compared with other forms of acupuncture, there was no significant difference in efficacy, suggesting that different acupuncture modalities may have comparable benefits. Regarding safety, scalp acupuncture demonstrated a superior profile, with significantly fewer adverse events compared with the control groups, confirming its characteristic as a low-risk intervention.

For patients suffering from insomnia, these results offer hope for an effective and safe therapeutic alternative to conventional medications. Scalp acupuncture may be particularly attractive for those who experience unwanted side effects with sleep medications or who prefer more natural approaches to treatment. For health professionals, these findings suggest that scalp acupuncture can be integrated into insomnia treatment protocols, especially as first-line treatment or in combination with other therapies. The technique appears promising not only for the demonstrated efficacy but also for the absence of significant adverse effects, a characteristic that distinguishes it favorably from pharmacologic treatments.

In addition, scalp acupuncture may offer long-term economic benefits, reducing dependence on medications and potentially decreasing costs associated with prolonged treatment of insomnia.

However, it is important to recognize the limitations of this study that may influence the interpretation of the results. The methodological quality of the included studies varied considerably, with only a few adequately implementing randomization techniques, allocation concealment, and blinded outcome assessment. This variability may have introduced bias into the results. In addition, publication bias was detected in the analyses, possibly related to the tendency to preferentially publish studies with positive results.

The heterogeneity observed between studies, especially in PSQI scores, suggests that different treatment protocols and patient characteristics may influence the results. The limited number of studies that reported adverse events also limits the robustness of conclusions about safety. Future studies should focus on more rigorous methodological designs, with larger samples, multiple centers, and standardized protocols to strengthen the evidence on the efficacy and safety of scalp acupuncture in the treatment of insomnia.