The genes identified with marijuana addiction have been identified as the same genes linked to depression and schizophrenia. The new research published in JAMA Psychiatry, studied 15,000 people and found that those at genetic risk for depression are more likely to get addicted to smoking pot. Though conflicting data has surfaced over the years, those with a predisposition to depression and schizophrenia are more likely to self medicate with routine marijuana use much like alcohol abuse, causing continued depression.