All suicidal people are deeply depressed. Although depression is often closely associated with suicidal feelings, not all people who kill themselves are obviously depressed. Also, people who are extremely depressed usually do not have the energy to kill themselves. There is no correlation between alcoholism and suicide. Alcoholics are prodded to suicidal behavior and even people who don't normally drink will often ingest alcohol shortly before killing themselves.
Suicidal people are mentally ill.
Once someone attempts suicide, that person will always entertain thoughts of suicide. Only about 10 percent of the people who attempt later kill themselves. If you ask someone about their suicidal intentions, you will only encourage them to kill themselves. Asking someone directly about their suicidal intentions will often lower their anxiety level and act as a deterrent to suicidal behavior by encouraging the ventilation of pent-up emotions through a frank discussion of his problems. Suicide is quite common among the lower class.