most frequently abused drug (88%). Furthermore, drug abuse preceded the first sign of schizophrenia by more than 1 year but typically by more than 5 years in 27.5% of patients. In 37.9% of individuals, drug abuse followed the first sign of schizophrenia, and in 34.6% of individuals the first sign of schizophrenia and drug abuse started within the same month. Related to the above, some studies suggest that cannabis and other substance use is associated with an earlier age of and more abrupt onset of psychotic symptoms in schizophrenic patients [4, 8, 11, 12, 37, 76, 84, 133, 149, 224, 226].
