Previous studies have shown that young adults who are susceptible to schizophrenia are more likely to develop it if they were heavy cannabis users at a younger age. As they get older it is less likely to develop, or they are better able to keep it from developing. My brother-in-law smoked cannabis in high school and college and was hospitalized for schizophrenia when he was in college. It wrecked his life and he still has schizophrenia at age 65. I don't think it is just an academic issue.