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Is “cannabis psychosis” a distinct category?

Graham Thornicroft, Graham Meadows, Pierluigi Politi

European Psychiatry 1992 DOI: 10.1017/s0924933800002157 (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Case-control study Peer reviewed
Sample size 45
Population Psychotic patients admitted to hospital, comprising 45 cases with cannabis-positive admission urinalysis and matched psychotic controls without evidence of cannabis use
Topics Cannabis
Citations 24
Key findings Cases with cannabis-positive urinalysis differed from controls only in being more likely to be Afro-Caribbean (P = 0.01), to show incoherent speech (P = 0.02), and to be agitated (P = 0.01); otherwise the groups were indistinguishable. The authors state these findings do not support the view that 'cannabis psychosis' has a distinct psycho-phenomenological pattern.

Abstract

Summary Forty-five cases of psychotic patients with admission urinalysis positive for cannabis were compared with psychotic controls without evidence of cannabis use. Cases and controls were matched for age, sex and year of admission, and were compared for socio-demographic data, circumstances of admission, diagnosis, and symptoms at admission. Three differences were found: cases were more likely to be Afro-Caribbean than white (P = 0.01), to manifest incoherence of speech (P= 0.02) and agitation (P= 0.01). In other respects the case and control groups were indistinguishable, and no pattern of symptoms characterised the “cannabis psychosis“group. These findings do not support the view that “cannabis psychosis” has a distinct psycho-phenomenological pattern Epidemiological studies are required to further clarify the association for psychotic patients between Afro-Caribbean ethnic groups and the likelihood of having a positive urine test for cannabis.