It is established the presence of seasonal variations in decompensation of patients with bipolar disorder. The purpose of this study is to assess whether other environmental factors such as Moon lighting or the distance between the Moon and Earth are associated with decompensation of this group of disorders.

We collected all the attention made ??to the Emergency Department of the Hospital de León for one year (July 2012 to June 2013). We identified patients diagnosed with Bipolar Disorder (F31.x). Consultations were correlated with the following astronomical data: Moon lighting, Moon Phase, Earth-Moon distance and growing or waning moon. Main variables to study were number of emergency consultations and income in hospitalization. It was used for analysis SPSS v20.

From a total of 1405 emergency consultations 96 patients were diagnosed with Bipolar Disorder, of whom 60 required hospitalization. The mean ratio of total number of consultations / total days in a particular moon phase was 0.2858 (95% CI: 0.2313 to 0.3403) with significant variations in the different phases. The mean ratio of total hospitalizations / total days in a particular moon phase was 0.1728 (95% CI: 0.1095 to 0.2361). The comparison of the mean lunar illumination between patients who required admission (mean = 56.7 + / -32.08) and those who were discharged (mean = 43.69 + / -32.39) was found near statistical significance (p = 0.058). There were no significant differences in the Earth-Moon distance or the waxing or waning state of the Moon.

No association was found between the Earth-Moon distance and the number of visits or hospitalizations in bipolar patients. The lunar illumination is higher in cases that required hospitalization and it is necessary conduct a study with a greater potency to establish or definitely reject this finding.