I come from a large family with alcoholic parents.
3 children are normal, 3 children with problems with either drinking or drugs.
Seems the 3 that had problems were the more "sensitive" types.
The 3 that are normal were the ones that fought back when parents were illogical or just plain wrong, where the other 3 internalized things.
I was always the "fixer", cleaning up messes and trying to making things smoother, trying to prevent fights.
Maybe taking things internally required "self medication"????