I'm reading a novel called Lonesome Dove that takes place in 1876 and at one point a character reminisces about how a lot of men he knew over the years "blew their heads off".
Would the tougher conditions of the past along with the ubiquity of guns lead to higher suicide rates relative to today?
This article answers your question, as it examines suicide during the Civil War and the years immediately afterwards, so it probably entails the entire 1860s and perhaps even beyond that.
The study found that 'the rate of suicide in the general population dramatically increased in the years following the war's end. During the Civil War, suicides occurred nearly every month, reliably peaking in the spring of each year. Depression and alcohol abuse were major factors associated with military suicides'.
So, I think the character was talking about veterans of the Civil War.