Continued use of a substance despite persistent or recurrent physical or psychological problems is one of the diagnostic criteria for substance dependence

This is the general catchall category of schizophrenia

a) disorganized schizophrenia b) undifferentiated schizophrenia c) paranoid schizophrenia d) catatonic schizophrenia

Until approximately 200 years ago, how many adults were illiterate?

a. all b. most c. half d. a quarter