The term “psychosis” is very broad. Substance users represent one group with particularly high rates of psychotic symptoms.

This review will present an update on cannabis and amphetamine-type Stimulant (ATS) and will try to differentiate and compare their associated psychotic features.

A systematic literature search was conducted from 1980 to date in the following databases: MEDLINE, PsycINFO and PubMed. Articles were included if they were highlighting substances induced psychoses, with particular emphasis on stimulants/amphetamine/methamphetamine and cannabis/marijuana induced psychoses, schizophrenia-spectrum disorder or schizophrenia.

There are many differences between these two substances regarding source, neurobiological processes, average latency periods before developing psychosis, clinical features as compared to schizophrenia, risk of using drugs and developing psychosis and drugs use and development of schizophrenia and urine screening test. With the recent proposals to regulate cannabis use, a further investigation of the association of this use with psychosis is required.

Our search elicited many studies of one substance and its association with psychosis but few comparative studies across substances. Yet in our opinion, these comparisons could shed further insight on the development of psychotic features.