First of all one has to find the cause of the depression:
What are symptoms of depression?
What are the Warning signs or suicide with depression?
These answers can be found at:
www.webmd.com/depression/default.htm (copy and paste in your search bar)
The causes and symptoms are too numerous to list here. They are extremely important to know and learn how to deal with them.
Depression carries a high risk of suicide. Anybody who expresses suicidal thoughts or intentions should be taken very, very seriously. Do not hesitate to call your local suicide hotline immediately. Call 1-800-SUICIDE (1-800-784-2433) or 1-800-273-TALK (1-800-273-8255) -- or the deaf hotline at 1-800-799-4TTY (1-800-799-4889).
If you or someone you know is demonstrating any of the warning signs of suicide with depression, either call your local suicide hot line, contact a mental health professional right away, or go to the emergency room for immediate treatment.