Dual diagnoses have same root?

Substance abuse and mental illness very commonly go together. One hypothesis to explain the correlation is to see the patient using alcohol/drugs to medicate the mental disorder. Another view sees the mental disorders as the symptoms of excessive drug/alcohol ingestion. Now comes Dr. Andrew Chambers and his researchers at the U of Indiana Medical school with a study that suggests both theories are wrong. Based on experiments with adult rats, Chambers found that both substance abuse and mental disorders probably stem from a malfunction in the amygdala, a small region within the brain that plays a role in numerous processes, including the memory of emotionally charged events. Read details. Read blogger Jason Schwartz's piece on the same issue, here.