Facebook is developing some tools to do this. Facebook took this decision as September 10th is observed as World Suicide Prevention Day. Users who post with suicidal emotions are going to be traced with these new tools. Facebook is going to help them by offering counselling sessions to them with the help of Samaritans trust. All the users are using facebook to express their emotions with their friends and family members.
With the new moderators, facebook is going to identify the users who are affected with depression. The users are provided with emotional support by the charity. This is offcourse, a great initiative by social media giant facebook. Hope this decreases the suicidal tendencies among the people.