http://articles.chicagotribune.com/2011-10-26/news/ct-x-1026-health-briefs-20111026_1_vitamin-d-deficiency-skin-sun-exposure

https://www.mayoclinic.org/diseases-conditions/teen-depression/symptoms-causes/syc-20350985?p=1

http://pulse.seattlechildrens.org/brain-discovery-could-lead-to-improved-treatments-for-depression/

http://www.nytimes.com/2013/07/02/magazine/the-half-trillion-dollar-depression.html

http://www.uab.edu/news/innovation/item/5650-classic-psychedelic-use-found-to-be-protective-with-regard-to-psychological-distress-and-suicidality-study-finds

http://www.mdmaptsd.org/news/94-landmark-study-shows-long-term-benefits-of-mdma-assisted-psychotherapy-for-ptsd-sufferers.html