As far as non pharmacological treatments go, bright light therapy shows the most promise for combatting the symptoms of SAD, or Seasonal Affective Disorder. Although the disorder technically applies to any cyclical depression that occurs at the same time each year, most cases of the disorder are linked to the colder months, making it almost colloquially synonymous with Winter Depression. Usually, the symptoms discussed in the video dissipate with the arrival of spring.

For more on the source of the body's circadian rhythms, which help our body tell day from night, read on here and here. For more explanation on melatonin, including its use in over the counter sleep aids, explore this article from Northwest Integrative Medicine or this study on sleep-wake regulation.