I always thought the same and that's why I hesitated going to the doctor or taking meds, but the truth is, I do have deep problems that caused me to get into all kinds of problems and burn all kinds of bridges. I completely wasted almost 10 years of my life battling with my mind. Now, that I'm on the meds, I realize that what happened with me wasn't just bad behavior or rebellion, it was my very own "Dark Passenger" and I'm glad to finally have control over it.
I think that we have made huge progress in understanding human psychology/psychiatry and that we are using this knowledge to save people from screwing up as much as I have. The biggest problem is figuring out when the problem is innate or created by the fear and knowledge of these disorders. So I think we are over-aware of these "problems of the mind" and that knowledge is screwing with us, thus creating huge spikes of new cases of the "current" disease.