What makes certain people reach that limit of no hope, giving up on everything and deciding to end it all, taking their own life?

Since the dawn of time there have been people who chose to take their own life. There are numerous methods, but most suicides are rooted in feelings of despair, desperation and grief.

Is it possible to intervene and prevent a suicide if acting in time? Is it possible to detect suicidal thoughts and act on them? What can be done?

Keynote speakers on suicide look at questions such as these, trying to understand this rather heavy subject.