As stated, (untreated) depression is the top cause of suicide, followed by other mental illnesses. What's interesting is that suicide is contagious. http://www

As stated, (untreated) depression is the top cause of suicide, followed by other mental illnesses. What's interesting is that suicide is contagious. http://www.nytimes.com/2014/08/14/upshot/the-science-behind-suicide-contagion.html?abt=0002&abg=0 http://www.nytimes.com/2014/08/14/upshot/the-science-behind-... Edit: The article is relatively weak. There's many more interesting case studies of nations and cultures that went from a near 0 suicide rate to sudden spikes.