These so called predictors of suicide can help us all be aware of and keen to this deadly potential within our friends and loved ones. While trained professionals may be more attuned to the subtleties of such predictors, there is no reason why caring non-professionals cannot contribute directly to the avoidance of suicide in people they know.
The major warning signs in order of significance are as follows: direct verbal warnings, having a suicide plan, having a history of suicide attempts, indirect statements and behaviors (e.g. sudden well-being, giving away treasured possessions, suggestions that the world might be "better off without me"), depression, hopelessness, intoxication, certain diagnostic groups (schizophrenics, mood disorders, borderline disorders), relatives of suicidal individuals, sex of the individual (men "succeed" more often, while women make more attempts), age (generally the older the client, the more likely they will actually kill themselves - with the exception of ages 15-24), race of the person (Caucasians kill themselves more than other groups), religion (Protestants more than Catholics or Jews suicide effectively), living alone, grieving the loss of a loved one, unemployment, serious or chronic illness, impulsivity, rigid thinking, excessive stress and recent release from hospital.
Once recognizing the presence of a number of these variables within the life of the person in crisis, the lay person can act accordingly. The goal is to insure that their friend/loved one gets the help they need and hence reduce or eliminate the potential for suicide. While it is likely impossible to stop an individual, who is truly committed to the idea of suicide, from acting out, it is often effective to encourage the part of the person that wants to live through the crisis. Clearly, most suicidal individuals hold both self destructive and life preserving feelings.
It is important to emphasize the feelings of caring for the suicidal person. Furthermore, it is important to help mobilize interpersonal resources of the person so that isolation is minimized. Focusing on the person's strengths, the desire to live while not minimizing their problems or their wish to die is also important. Clarifying the idea that the problems that created the crisis can be solved while offering realistic hope is helpful in this situation. Just as the professional may employ a verbal "contract", specifying that the client is to call before attempting suicide, so too the friend/loved one may employ the same principle. Just as important as the personal intervention is the strong encouragement to seek professional help in order to provide more permanent solutions to the problems.