Lesson 2: Unique Disorders

Abnormal Behaviour and the Moon

Popular folklore (and Hollywood movies) links the presence of a full moon to an increase in abnormal behaviour, specifically negative behaviour such as suicide and aggression. According to this notion, individuals who succumb to the forces of the full moon are, in fact, lunatics (lunacy). Table 10.1 summarizes research data (www.faculty.washington.edu/chudler/moon.html) concerning behaviour and a full moon.

Table 10.1: Abnormal Behaviour During a Full Moon

Behaviour	Significance
Aggravated assault within the general population	Occurs more often during a full moon
Overall crime	Occurs more often during a full moon
Arrests by police	No difference between full moon and other phases of the moon
911 calls received by operators	No difference between full moon and other phases of the moon
Aggression and violence by psychiatric patients	No difference between full moon and other phases of the moon
Aggression and violence by nursing home patients	No difference between full moon and other phases of the moon
Aggression and violence by males in prison	No difference between full moon and other phases of the moon
Admissions to psychiatric hospitals	An increase with the new moon but a decrease with a full moon
Therapy sessions regarding anxiety and depression	No difference between full moon and other phases of the moon
Psychiatric emergency room visits	An increase with the quarter moon and a decrease with a new and full moon
Suicides	No difference between full moon and other phases of the moon
Unintentional self-poisonings	Occurs more often during a full moon
Emergency and trauma-based admissions to hospitals	No difference between full moon and other phases of the moon
Calls to suicide help-lines	An increase with the new moon and first quarter; no change in other phases of the lunar cycle
General calls to crisis help-lines	No difference between full moon and other phases of the moon
Heart attacks	No difference between full moon and other phases of the moon
Oral and jaw-related admissions to hospitals	No difference between full moon and other phases of the moon
Drug overdoses	No difference between full moon and other phases of the moon
Traffic accidents with property damage	No difference between full moon and other phases of the moon. An increase is observed on Fridays and Saturdays, however, as well as on Halloween, New Year’s Eve, and Thanksgiving.
Traffic accidents with non-fatal injuries	No difference between full moon and other phases of the moon. An increase is observed on Fridays and Saturdays, however, as well as on Halloween, New Year’s Eve, and Thanksgiving.
Motor vehicle accidents	No difference between full moon and other phases of the moon
Animal bites	Occurs more often during a full moon in one study, but no difference in another
Heart rate after exercise	Is greater during a full moon

As you may have noticed, some of the data in Table 10.1 contradicts other data in the same table. These inconsistencies may make one wonder about the validity of the studies conducted surrounding abnormal behaviour and the full moon. In fact, from the research that has been done, it appears there is no correlation (statistical relationship) between abnormal behaviour and the lunar cycle. To confirm this assumption further studies are required. Confounding factors must be considered, such as those linked to incomplete data and the belief systems of the study participants. For example, if people believe that a full moon affects behaviour, then they may better recall odd events that happen in the period of the full moon. They may also have difficulty remembering similar events that occur during other phases of the lunar cycle.