The relationship between cannabis use and psychosis has long been a question of interest.1,2 Heavy cannabis use itself has been linked to features of schizophrenia, notably psychotic-like experiences (PLEs), cognitive difficulties, and negative symptoms such as social withdrawal and depressed mood.3–6 In challenge paradigms, it has been shown that administration of delta-9-tetrahydrocannabinol (THC; the principal psychoactive constituent in cannabis) can induce acute, transitory PLEs7–9 that often include forms of unusual thought content, paranoia, and disorganized thinking; auditory and visual hallucinations are rarer.3,8,9 While self-reported PLEs are often transitory, subclinical, and much more common in the general population than psychotic disorders,10 they are considered indices of psychopathology and are associated with impairment. Some risk factors appear to make it more likely that cannabis users will report these PLEs, including early age of cannabis initiation,4 heavy cannabis use,6 and consumption of high-potency strains of cannabis.5
