How can a person be "depressed" and not suicidal? is it because they are abusing substances-food, smoke, alcohol-on a regular basis?

Suicide & Substances: Suicidal thinking is a common, though not necessary, symptom of major depression. Self-medicating with substances is certainly common in individuals who have no access to health care or who are unaware of their options to treat their mood in more adaptive ways. The overuse of alcohol is especially damaging, since, as a depressant, it can intensify a depressive episode in the long run.

Depression: Mild to moderate depression is not generally accompanied by suicidal thoughts. Substance abuse does increase depressive feelings and can lead to suicidal ideation. If you are depressed consult with a mental health professional, most people with depression can be helped. Best wishes.

Degree of depression: You seem to feel that if a person is not suicidal, s/he cannot be depressed. Or that s/he has somehow caused the problem by abusing substances. It's true that those activities will worsen depression; many people also do them hoping to somehow ameliorate pain. Then the substance abuse complicates things a lot. If you'd like to learn about depression, see nimh: http://tinyurl.Com/2jbqb8.