Does the full moon really affect people’s moods and behavior? I’ve heard stories about increased crime rates, more hospital admissions, and generally erratic behavior during a full moon. Is there any scientific evidence to support these claims, or are they just myths and folklore? Specifically, what studies have been conducted on the lunar effect and what were their findings? If some studies show a correlation, what are the proposed mechanisms behind how the full moon could possibly influence human psychology and physiology? I’m interested in understanding the different perspectives and whether there’s any consensus in the scientific community regarding the “lunar effect.”

Answer

While the belief that the full moon affects people’s moods and behavior is widespread, scientific evidence does not consistently support this claim. This belief is often referred to as the "lunar effect" or "Transylvania effect."

Lack of Consistent Evidence:

• Meta-analyses and Reviews: Numerous studies have investigated the potential link between lunar cycles and various aspects of human behavior, including mood, sleep, mental health, crime rates, hospital admissions, and emergency room visits. Many meta-analyses (studies that combine the results of multiple studies) and reviews have concluded that there is no significant correlation between the full moon and these phenomena.
• Inconsistent Findings: Individual studies sometimes report a correlation, but these findings are often not replicated in subsequent research or are subject to methodological flaws. The lack of consistent results across different studies makes it difficult to draw firm conclusions.
• Publication Bias: Studies that find a statistically significant effect of the full moon are more likely to be published than studies that find no effect. This publication bias can create a skewed impression of the evidence.

Potential Explanations for Perceived Lunar Effects:

• Confirmation Bias: People may be more likely to notice and remember events that occur during a full moon, reinforcing their belief in the lunar effect. This is an example of confirmation bias, where individuals selectively attend to information that confirms their existing beliefs.
• Cultural Beliefs and Expectations: Strong cultural beliefs about the full moon’s influence can shape people’s perceptions and behaviors. If people expect the full moon to cause unusual behavior, they may be more likely to interpret ambiguous events as evidence of its influence.
• Circadian Rhythms: Light can suppress the production of melatonin, a hormone that promotes sleep. However, the amount of light produced by a full moon is generally considered too dim to have a significant impact on most people’s circadian rhythms.

Specific Areas of Research:

• Sleep: Some studies have suggested a possible association between the full moon and changes in sleep patterns, such as reduced sleep duration or altered sleep stages. However, these findings are not consistent, and the effect size is typically small.
• Mental Health: Studies examining the link between lunar cycles and mental health conditions, such as bipolar disorder or anxiety, have generally not found a consistent relationship.
• Crime and Violence: The idea that crime rates increase during the full moon has been investigated extensively. The majority of studies have found no significant correlation.
• Emergency Room Visits and Hospital Admissions: Similarly, research on the association between the full moon and emergency room visits or hospital admissions has generally not supported the claim of a lunar effect.

Conclusion:

While the belief in the lunar effect persists, scientific evidence does not consistently support the idea that the full moon significantly affects people’s moods or behavior. The perceived lunar effect is likely due to a combination of confirmation bias, cultural beliefs, and other factors rather than a direct influence of the moon itself. However, research continues in this area.