Schizophrenic psychoses are often associated with the use of cannabis. This review article summarizes the existing evidence for a possible causal relationship between the use of cannabis and the development of schizophrenia. In this context, epidemiologic studies were able to consistently identify the use of cannabis as a relevant risk factor. Of note, the risk for the development of schizophrenia particularly depends on the interaction between cannabis and other risk factors, such as genetic vulnerability, childhood trauma and the composition and potency of the cannabis preparations. In addition, the different cannabis-associated psychotic manifestations are described, differentiated according to the onset, duration and clinical significance of psychosis and classified according to ICD-10 diagnostic criteria. Finally, the consequences of cannabis use on psychopathology, psychosocial functioning, risk for psychotic relapses and treatment adherence in schizophrenia patients as well as the positive effects of continued abstinence on the clinical course are presented in more detail.