Exploring the Influence of Lunar Phases on Neuropsychiatric Conditions: A Scoping Review of Evidence, Concepts, and Gaps

Background/Objectives: The influence of the lunar cycle on human psychology and behavior has been an intriguing subject, surrounded by historical beliefs and folklore. This scoping review aims to synthesize the existing research on the relationship between the lunar cycle and neuropsychiatric disorders, identifying potential confounders and gaps in the literature. Methods: A preliminary search on MEDLINE was conducted to identify foundational studies and establish relevant MeSH terms. Using these terms, a comprehensive search was performed across the major databases including PubMed, EMBASE, PsycINFO, and Web of Science. In addition, a manual search of reference lists was undertaken through Google Scholar. After applying inclusion and exclusion criteria, 70 studies were selected for the detailed analysis in the scoping review. The studies were evaluated for their methodological quality and the consistency of reported findings. Results: Cultural and historical beliefs about the moon’s impact on behavior remain prevalent and often dominate the scientific discourse. Proposed mechanisms for lunar influence include gravitational effects on human physiology, sleep disturbances due to full moon illumination, and disruptions of circadian or circalunar rhythms. Psychological conditioning and cognitive biases, especially among mental health practitioners, may also reinforce belief in a moon-mind connection. Certain regions of the world, such as Asian and Scandinavian countries, have consistently reported lunar associations, while evidence remains inconclusive from a global perspective. Conclusion: Existing studies both support and refute lunar associations with neuropsychiatric disorders. Methodological flaws and the impact of artificial illumination in the modern settings highlight the need for future studies with scholarly rigor to establish definitive conclusions on this topic.