This is interesting take, because in my readings from first person accounts about the development of schizophrenia, some people feel that having started substance abuse from a young age as well having abused a variety have led to the psychiatric diagnosis. It kind of sounds like the chicken-egg argument. I have also read that substance abuse is used as coping/self medication for an already existing undiagnosed underlying mental illness.
For the original poster, NA may be a beginning for getting some help. There are also programs designed for early diagnosis and treatment of a mental illness. I'm not sure where you are located but if you look up prodome, prodormal states, early intervention prevention support there are several facilities in the United States.