Substance use disorder and schizophrenia

Substance-use disorders are a group of cognitive, behavioural, and physiological symptoms indicating that the individual continues to use a substance despite problems related to the use of that substance.^{[APA, 2013, pg. 483]} Substances can include alcohol, cannabis, hallucinogens, opioids, sedatives, and tobacco.^{[APA, 2013, pg. 482]} Substance-use disorders are typified by craving of a substance, tolerance, withdrawal symptoms, and continued use of a substance despite negative consequences, amongst other criteria.^{[APA, 2013, pg. 509]} Differentiating schizophrenia from the psychosis that can be experienced as a result of substance use focusses on the timeframe of the psychotic symptoms.^{[APA, 2013]} In schizophrenia, the psychotic symptoms are persistent and not attributable to the effects of a substance.^{[APA, 2013, pg. 105]}

References:
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. Fifth Edition (DSM-5™). © American Psychiatric Association, 2013.

Buckley PF, Miller BJ, Lehrer DS, Castle DJ. Psychiatric comorbidities and schizophrenia. Schizophr Bull 2009; 35 (2): 383–402.

Regier DA, Farmer ME, Rae DS, et al. Comorbidity of mental disorders with alcohol and other drug abuse. Results from the Epidemiologic Catchment Area (ECA) Study. JAMA 1990; 264 (19): 2511–2518.