depression is a symptom that makes a person think bad things about themselves,if someone is depressed it would make the person think they are worthless or not wanted, if a person is suicidal then they would think worst things about themselves,for a example if you are suicidal then you would think that there is no reason to live or there isnt a point of trying.If you are suicidal then it would be worst and they would need to be watched constantly and would need to go to therapy,but if they are depressed it still bad but not as bad as being suicidal