THERE ARE DAYS ... AND MOONS - SELF-POISONING IS NOT LUNACY

Objective: To determine whether there are significant circadian, weekl y or lunar variations in self-poisoning presentations and whether pati ents' names or dates of birth have an influence on the likelihood of s elf-poisoning by analysing biorhythms, numerology and star sign. Setti ng: Hunter Valley, Australia. Subjects: Consecutive adult patients adm itted with self-poisoning between January 1987 and June 1993. Results: There were 2215 patients admitted. There was a marked circadian varia tion. Over 6% of all admissions occurred in each of the hours between 6 p.m. and 1 a.m. compared with less than 2% per hour between 5 a.m. a nd 9 a.m. This pattern was not different for patients with a diagnosis of depression. Numerology, biorhythms and star signs had no significa nt correlations with self-poisoning, nor was there a significant weekl y or yearly variation in presentations. There was a small but statisti cally significant sex difference in presentations analysed by lunar ph ases. At the new moon 60% of self-poisonings were in women, compared w ith 45% when the moon was full. The odds ratios (OR) for women to be a dmitted at full moon and at new moon were 1.27 (95% confidence interva l [CI], 0.92-1.66; P value not significant) and 0.73 (95% CI, 0.57-0.9 2; P = 0.009) respectively. The mean illumination of the moon at the t ime of overdose was 50.63% +/- 0.91% for men, compared with 47.45% +/- 0.85% for women (P= 0.014). Conclusion: The circadian cycle (but not weekly, yearly or mystical cycles) should be taken into account when d etermining staffing levels for poison information and casualty service s. The full moon is protective for women.