The functions you can think of like physical organs. Sometimes a person might have an illness that affects the heart or lungs, for example, that has nothing to do with either the heart or the lungs. Same goes with the functions. You might have someone with a serious pathology but whose functions work just fine. Or you might have someone whose functions are seriously out of balance (like overuse of the superior function, or being in the grip of the inferior function) who also produces pathological effects. So its hard to simply say "X person is such a way because of their functions." Jung believed that most psychological problems were problems of dissociation, and this is generally still commonly held today. We first look to the complexes to see what's going on there (for example people with Borderline often have major swings of affect, good positive feelings one minute, and terribly sickly feelings the next). The functions, being only a subset of one complex (the ego) may only influence how the pathology comes across in that person, but may not be the cause of the pathology itself.