"Habit" might be a better word for it. A behavior can become habitual: a knee-jerk reaction to emotional or environmental stimuli. I think that's different from an addiction, which is a disease with biochemical and perhaps genetic components. Someone might need to get angry to alleviate anxiety that's building up inside him or her, but it still strikes me as different from the person who needs a cigarette.

Does a person who constantly gets angry feel relief after blowing up? I doubt it. But you tell me.

Elmer