Mental Health Disorders and Full Moon: Is There a Link?

We spoke to Dr Alfred Samuel, Psychiatrist, Holy Cross Hospital, Kerala to understand more about the connection between mental health disorders and full moon.

It is well known that human physiology is affected by seasonal and circadian rhythms. However, the effect of lunar cycles on human physiology and behaviour is debatable. We spoke to Dr Alfred Samuel, Psychiatrist, Holy Cross Hospital, Kerala to understand more about this connection.

For centuries, physicians and philosophers believed that the full moon influenced human behaviour. Various theories were hypothesized to link lunar cycles and human mental health. Among them, the most popular is the effect of the full moon on circadian rhythm. Changes in circadian rhythm are associated with an increase in:

1. Anxiety
2. Bipolar disorder
3. Depression, or schizophrenia

However, data from previous research in this regard is conflicting. A study also reported a link between three different lunar cycles and rapid bipolar mood cycles reported.

A single-site study from Goa, India, reported a significantly greater number of patients with non-affective psychoses reporting to a psychiatric hospital on full moon days. However, this trend was not true for mania or depression. In a more recent analysis from 2017, the number of psychiatric presentations to a hospital's emergency department and the four phases of the lunar cycle were not related. A 2019 review of nearly 18,000 medical records also found no relation between lunar cycles and the length of hospital stays or the number of inpatient admissions or discharges at psychiatric facilities.

A more recent study analysing the relation between the lunar phases and sleep in humans reported that sleep starts later and is shorter on the nights before the full moon. Another study reported that near to full moon, stage 4 and rapid eye movement (REM) sleep were reduced in women, while in men the REM duration increased. However, in children, no such change in sleep duration was seen.

Interestingly, a study involving 17 bipolar patients reported a link between three different lunar cycles and rapid bipolar mood cycles. The onset of mania in bipolar patients was associated with marked changes in total sleep time. It was consistent with the lunar month variation of total sleep time in healthy individuals.

More evidence is required before a general conclusion can be made on whether there is a link between mental health disorders and the lunar cycle. Till then, let us "Say Yes to Life" and be not fooled by common misconceptions about mental health.