Should people who are severly depresed and do not respond to treatment commit suicide?

No. There are more than jusr drugs for treatment. Besides, people with depression who kill themselves do it when they start to feel better. Strange I know, but when people are rock bottom depressed they feel that they aren't confident enough to kill themselves. It's when their self-worth starts to go up that they do it. They are still depressed, but not rock bottom depressed.