The belief that the lunar cycle is associated with the onset and severity of psychiatric symptoms has persisted since the middle ages [
The belief that the lunar cycle influences the frequency and severity of emergency psychiatric presentations is clearly widespread. However, few studies conducted to date have found consistent evidence in support of a lunar effect [
Despite being in the minority, some retrospective studies have found a relationship between the frequency of criminal behaviour or psychiatric crises and the lunar cycle [
Thus, the research performed in this area to date does not demonstrate a consistent relationship between emergency psychiatric admissions and the lunar cycle. The response to this lack of consistency has been to replicate previous studies looking for different results. We, however, propose that these inconsistent results may be due to the wide variety of definitions of the “full-moon” timeframe used in previous lunar research.
Therefore, in this study, we analyzed the relationship between the lunar cycle and the frequency of emergency psychiatric presentations in one population using three different methods of defining the “full-moon” timeframe. In the first model, we defined the full-moon period as the 12 hours surrounding the full moon. In the second model, we defined the full moon as a 24-hour period including the 12 hours before and after the time of the full moon. In the third model, we defined the full-moon period as a three-day period consisting of 24 hours before and after the 24-hour period surrounding the time of the full moon.
These definitions of the full-moon period are found in lunar research because they are thought to ensure that the study captures both the potential direct effects of the full moon (12 hours) and the potential effect of the waxing and waning moon (24 hours and the 3-day period). We hypothesized that each model will yield different psychiatric diagnoses and presentation characteristics (e.g., mode of arrival and triage severity) for ED presentations during the full-moon period specified by that model.
This study was conducted using data from two tertiary care centers in Kingston, Ontario. We obtained our data from an administrative database maintained by Hotel Dieu Hospital (HDH) and Kingston General Hospital (KGH). These databases recorded all presentations to the EDs of these hospitals. We included presentations if they were categorized as “Mental Health and Psychosocial Condition” over a five-year period. We included the following information about each presentation in our data set: date and time of presentation, triage severity, and mode of arrival. We also included the following patient characteristics: gender, marital status, age, and primary diagnosis.
We then grouped the primary diagnoses into the following diagnostic clusters: dementia, delirium and cognitive disorders; substance-related disorders; schizophrenia and psychotic disorders; mood disorders; adjustment disorders; anxiety disorders; somatoform and dissociative disorders; eating disorders; personality disorders; childhood disorders; and other disorders.
Next, we categorized ED presentations based on whether they occurred during the period defined by one of the full-moon models that we tested. We calculated all of the full-moon periods using the exact time of the full moon, which we obtained from tables available on the NASA website [
In the 12-hour model, we defined all presentations that occurred within the 6 hours preceding or following the time of the full moon as “full-moon” presentations. In the 24-hour model, we defined all presentations that occurred within 12 hours preceding or following the time of the full moon as “full-moon” presentations. In the 3-day model, we defined all presentations that occurred 24 hours before or after the 24 hours surrounding the time of the full moon as “full-moon” presentations.
We used SPSS version 20.0 to analyze the data. We conducted independent samples
Prior to the commencement of this study, ethical approval was obtained from the Queen’s University Health Sciences Research Ethics Board.
A total of 9,967 presentations were made to the ED for Mental Health and Psychosocial Condition during the 5-year study period. Of the total population, 54% were male (
Demographics for the 12-hour, 24 hour, and 3-day full moon models can be found in Tables
Frequencies and percentages for psychiatric ED presentations for the 12-hour model.
Characteristic | 12 hr full-moon period ( |
All other times ( |
||||
---|---|---|---|---|---|---|
|
M (SD) | Percent |
|
M (SD) | Percent | |
Age | 36.18 (18.91) | 36.06 (18.98) | ||||
Gender | ||||||
Male | 97 | 57.1 | 5289 | 54.0 | ||
Female | 73 | 42.9 | 4507 | 46.0 | ||
Marital status | ||||||
Married | 21 | 12.5 | 1447 | 15.0 | ||
Single | 100 | 59.5 | 5951 | 61.7 | ||
Divorced | 13 | 7.7 | 613 | 6.4 | ||
Separated | 6 | 3.6 | 513 | 5.3 | ||
Widowed | 6 | 3.6 | 360 | 3.7 | ||
Common-law | 22 | 13.1 | 767 | 7.9 | ||
Primary diagnosis | ||||||
Dementia, delirium, and cognitive disorders | 3 | 1.8 | 201 | 2.1 | ||
Substance-related disorders | 75 | 44.1 | 3848 | 39.3 | ||
Schizophrenia and psychotic disorders | 11 | 6.5 | 563 | 5.7 | ||
Mood disorders | 17 | 10 | 961 | 9.8 | ||
Adjustment disorders | 18 | 10.6 | 772 | 7.9 | ||
Anxiety disorders | 29 | 17.1 | 2464 | 25.2 | ||
Somatoform and dissociative disorders | 3 | 1.8 | 230 | 2.3 | ||
Eating disorders | 0 | 0 | 42 | 0.4 | ||
Personality disorders | 3 | 1.8 | 115 | 1.2 | ||
Childhood disorders | 3 | 1.8 | 295 | 3 | ||
Others | 8 | 4.7 | 305 | 3.1 | ||
Arrival mode | ||||||
Ground ambulance | 59 | 34.7 | 3387 | 34.6 | ||
Others | 1 | 0.6 | 28 | 0.3 | ||
Police | 12 | 7.1 | 643 | 6.6 | ||
Walk-in | 98 | 57.6 | 5719 | 58.4 | ||
Triage code | ||||||
Emergent | 28 | 16.5 | 936 | 9.6 | ||
Less urgent | 55 | 32.4 | 3027 | 30.9 | ||
Nonurgent | 6 | 3.5 | 444 | 4.5 | ||
Resuscitation | 1 | 0.6 | 33 | 0.3 | ||
Unavailable | 0 | 0.0 | 1 | 0 | ||
Urgent | 80 | 47.1 | 5356 | 54.7 |
Frequencies and percentages for psychiatric ED presentations for the 24-hour model.
Characteristic | 24 hr full-moon period ( |
All other times ( |
||||
---|---|---|---|---|---|---|
|
M (SD) | Percent |
|
M (SD) | Percent | |
Age | 37.06 (19.98) | 36.03 (18.95) | ||||
Gender | ||||||
Male | 178 | 57.4 | 5208 | 53.9 | ||
Female | 132 | 42.6 | 4448 | 46.1 | ||
Marital status | ||||||
Married | 39 | 12.8 | 1429 | 15 | ||
Single | 187 | 61.3 | 5864 | 61.6 | ||
Divorced | 17 | 5.6 | 609 | 6.4 | ||
Separated | 11 | 3.6 | 508 | 5.3 | ||
Widowed | 16 | 5.2 | 350 | 3.7 | ||
Common-law | 35 | 11.5 | 754 | 7.9 | ||
Primary diagnosis | ||||||
Dementia, delirium, and cognitive disorders | 6 | 1.9 | 198 | 2.0 | ||
Substance-related disorders | 131 | 42.3 | 3792 | 39.3 | ||
Schizophrenia and psychotic disorders | 25 | 8.1 | 549 | 5.7 | ||
Mood disorders | 28 | 9 | 950 | 9.8 | ||
Adjustment disorders | 26 | 8.4 | 764 | 7.9 | ||
Anxiety disorders | 60 | 19.4 | 2433 | 25.2 | ||
Somatoform and dissociative disorders | 6 | 1.9 | 227 | 2.4 | ||
Eating disorders | 0 | 0 | 43 | 0.4 | ||
Personality disorders | 8 | 2.6 | 110 | 1.1 | ||
Childhood disorders | 8 | 2.6 | 290 | 3 | ||
Others | 12 | 3.9 | 301 | 3.1 | ||
Arrival mode | ||||||
Ground ambulance | 110 | 35.5 | 3336 | 34.5 | ||
Others | 1 | 0.3 | 28 | 0.3 | ||
Police | 18 | 5.8 | 637 | 6.6 | ||
Walk-in | 179 | 57.7 | 5638 | 58.4 | ||
Triage code | ||||||
Emergent | 44 | 14.2 | 920 | 9.5 | ||
Less urgent | 97 | 31.3 | 2985 | 30.9 | ||
Nonurgent | 8 | 2.6 | 442 | 4.6 | ||
Resuscitation | 1 | 0.3 | 33 | 0.3 | ||
Unavailable | 0 | 0 | 1 | 0 | ||
Urgent | 160 | 51.6 | 5276 | 54.6 |
Frequencies and percentages for psychiatric ED presentations for the 3-day model.
Characteristic | 3-day full-moon period ( |
All other times ( |
||||
---|---|---|---|---|---|---|
|
M (SD) | Percent |
|
M (SD) | Percent | |
Age | 35.72 (18.79) | 36.10 (19.00) | ||||
Gender | ||||||
Male | 540 | 53.1 | 4846 | 54.1 | ||
Female | 476 | 46.9 | 4104 | 45.9 | ||
Marital status | ||||||
Married | 148 | 14.8 | 1320 | 15.0 | ||
Single | 603 | 60.2 | 5448 | 61.8 | ||
Divorced | 61 | 6.1 | 565 | 6.4 | ||
Separated | 54 | 5.4 | 465 | 5.3 | ||
Widowed | 46 | 4.6 | 320 | 3.6 | ||
Common-law | 89 | 8.9 | 700 | 7.9 | ||
Primary diagnosis | ||||||
Dementia, delirium, and cognitive disorders | 20 | 2.0 | 184 | 2.1 | ||
Substance-related disorders | 407 | 40.1 | 3516 | 39.3 | ||
Schizophrenia and psychotic disorders | 70 | 6.9 | 504 | 5.6 | ||
Mood disorders | 95 | 9.4 | 883 | 9.9 | ||
Adjustment disorders | 77 | 7.6 | 713 | 8.0 | ||
Anxiety disorders | 248 | 24.4 | 2245 | 25.1 | ||
Somatoform and dissociative disorders | 21 | 2.1 | 212 | 2.4 | ||
Eating disorders | 5 | 0.5 | 38 | 0.4 | ||
Personality disorders | 13 | 1.3 | 105 | 1.2 | ||
Childhood disorders | 29 | 2.9 | 269 | 3.0 | ||
Others | 31 | 3.1 | 282 | 3.2 | ||
Arrival mode | ||||||
Ground ambulance | 340 | 33.5 | 3106 | 34.7 | ||
Others | 3 | 0.3 | 26 | 0.3 | ||
Police | 72 | 7.1 | 583 | 6.5 | ||
Walk-in | 598 | 58.9 | 5219 | 58.3 | ||
Triage code | ||||||
Emergent | 98 | 9.6 | 866 | 9.7 | ||
Less urgent | 308 | 30.3 | 2774 | 31 | ||
Nonurgent | 46 | 4.5 | 404 | 4.5 | ||
Resuscitation | 4 | 0.4 | 30 | 0.3 | ||
Unavailable | 0 | 0.0 | 1 | 0.0 | ||
Urgent | 560 | 55.1 | 4876 | 54.5 |
In the 12-hour full-moon model, we found that significantly fewer patients with anxiety disorders presented to the ED compared to the non-full-moon period (
In the 24-hour model, we again found that significantly fewer patients with anxiety presented during the full-moon period (
The 3-day model did not show any statistically significant differences between presentations that occurred during the full-moon period and the non-full-moon period.
We analyzed three definitional models of the full-moon period within the same population and found different significant results for each model. The results of previous lunar research have been equally contradictory. The majority of studies conducted to date have found that the lunar cycle does not have a significant effect on psychiatric ED presentations [
The results of our study seem to support the findings of both kinds of research. Consistent with the majority of lunar research, we found that the lunar cycle did not influence ED presentations in the 3-day model. However, in the 12-hour and 24-hour models, we found a significant effect of the lunar cycle such that the frequency of psychiatric ED presentations was reduced during the full moon. We also found that significantly more patients with a diagnosis of personality disorder presented during the 24 hr full-moon period and that triage codes during this time tended to be more severe. These results support the minority of lunar research, which has found an effect of the lunar cycle. Our results are clearly contradictory and provide a good representation of the confusion that exists in lunar research. However, our study is the first of its kind conducted to test the validity of common lunar models used in lunar research within the same population. Our study may be used to provide an explanation for the conflicting findings about the relationship between the lunar cycle and the frequency or severity of psychiatric emergencies discovered by other researchers [
Although methodological issues may explain the conflicting research findings in this area, this does not explain why the belief in a lunar effect continues to be so widespread. One plausible explanation is that this belief is a cultural artifact, left over from the time before artificial lighting, when the lunar cycle had a real influence on the severity of bipolar and epileptic symptoms [
Although our study provides a compelling explanation for the discrepancies in lunar research, it is the first of its kind and has several limitations. We chose three of the more commonly used definitions, but there are others that we did not test, such as a 6-hour, 7-day, and a lunar quartile model. Future research should include these alternate definitions of the full moon period. We also only looked at data from one centre and at psychiatric admissions. Future studies may wish to look at more centers and different diagnoses (such as maternity admissions).
This study found differences in psychiatric ED admissions during the full moon period, depending on the definition of “full moon.” Our findings highlight the need for a consistent definition of “full moon.” This lack of a consistent definition of the full-moon period may explain the conflicting findings of previous studies in this area.
The authors have no financial or other conflict of interests to disclose.