Entrainment of bipolar mood cycles by lunar cycles
This view shows the thin crescent Moon setting over ESO’s Paranal Observatory in Chile. As well as the bright crescent the rest of the disc of the Moon can be faintly seen. This phenomenon is called earthshine. It is due to sunlight reflecting off the Earth and illuminating the lunar surface. By observing earthshine astronomers can study the properties of light reflected from Earth as if it were an exoplanet and search for signs of life. This picture was taken on 27 October 2011 and also records the planets Mercury and Venus.

Entrainment of bipolar mood cycles by lunar cycles

Image by eso.org.

A new study by T. Wehr found some evidence that lunar cycles can entrain mood cycles in patients with bipolar depression. Dr. Wehr found in some patients similar periodicities in their mood cycles which were synchronous with multiples of bi-weekly lunar tidal cycles:

T A Wehr; Bipolar mood cycles and lunar tidal cycles Molecular Psychiatry advance online publication 24 January 2017; doi: 10.1038/mp.2016.263