Suicide rarely comes up as a preparedness topic, mostly because preppers are proactively looking for ways to survive whatever happens, not check out permanently. But suicide is a topic that everyone should be familiar with as it affects many, many families in our community--maybe even yours--and the incidence of suicides are rising dramatically.
Data from 2012 shows that 64% of all gun-related deaths in the US were suicide--not homicides, not using a gun to protect yourself, but people choosing a quick and effective way to kill themselves. Needless to say, since many preppers also own guns, the possibility of your gun being used by someone, quite possibly a family member, to commit suicide, should make all of us more aware of the need to safeguard our weapons from someone who would use them in this manner.
Most importantly, however, is the ability to get help for someone who is feeling suicidal. You can do this by knowing the risk factors and warnings of suicide, knowing who to call for help when someone is feeling suicidal, and talking to someone you suspect may be suicidal.
On a related note, our military suicide numbers are even more staggering than that of the civilian population (nearly double). A lot has been written about veterans and suicide (here, here, and here) but a definitive solution has yet to be found. If you know a veteran/active duty military member who may be suicidal, the Veterans Crisis Line is there to help.