Effect of the full moon on a sample of developmentally delayed, institutionalized women

Over 19 lunar months reports of all aggressive acting-out misbehaviors as recorded by direct-care staff were evaluated and recorded on a day-by-day basis for a randomly selected sample of 20 developmentally delayed women, CA 18 to 50; MA, 9 to 18 months. All had been in continuous residence in a residential treatment center for a minimum of 31 months. A grid representing the 24-hr. period of the full moon (a), the three days prior to the day of the full moon (b), the three days after the full moon (c), and the balance of the lunar period (d) was placed over the record. Comparisons using the Duncan multiple-range test indicated that the mean number of misbehaviors on the day of the full moon was significantly higher than the mean number on any other day of the lunar period (the next highest was for the three days prior to the day of the full moon).