There are different intensities of trauma, just like one can scrape their knee when tripping...or crack their skull open (same fall, just different landings).
Emotional traumas are the same, what is "minor" to one person, might be "life-altering" to another...so yes, one might be heavily addicted to smoking, drugs, sex, etc...but a single severe event can change the wiring of the brain (and the mind's ability to interpret those inputs) to the degree that former habits are dropped, or that new habits are adopted.
There is no "normal" when it comes to healing from trauma. Some similarities, yes, but only in general patterns, not specific events and outcomes.