Psicosis inducida por cannabis: características clínicas y su diferenciación con la esquizofrenia con y sin consumo de cannabis asociado

Cannabis use is a known risk factor for psychosis. Among three inpatient groups—cannabis-induced psychosis, schizophrenia with cannabis use, and schizophrenia without cannabis use—those with cannabis-induced psychosis had lower negative symptom scores, fewer auditory hallucinations, and more mania than those with schizophrenia and cannabis use. Few clinical differences appeared between schizophrenia groups regardless of cannabis history. The age of first admission for psychosis was lower in both cannabis-using groups, suggesting cannabis precipitates psychotic symptoms.

Study at a glance

Abstract

Cannabis use is considered an established risk factor for psychosis development. Differentiating between cannabis-induced disorders and schizophrenia is useful for prognostic and therapeutic purposes. Three inpatients groups were differentiated: cannabis-induced psychosis (CIP) (n = 69; mean age = 27.4, SD = 6.5; 82.6% males), schizophrenia with cannabis abuse or dependence (SZ + CB) (n = 57; mean age = 31.9, SD = 10.1; 94.7% males) and schizophrenia without cannabis abuse or dependence (SZ) (n = 181; mean age = 41.8, SD = 13.3; 54.1% males). The Psychiatric Research Interview for Substance and Mental Disorders (PRISM-IV) scale was used to differentiate induced psychosis. The CIP group presented lower mean scores on the negative PANSS subscale (M = 12.9, SD = 5.9; F = 32.24, p < 0.001), fewer auditory hallucinations (60.3%; X² = 6.60, p = 0.037) and greater presence of mania (26.1% vs. 12.3%; X² = 32.58, p < 0.001) than the SZ + CB group. There were few clinical differences between patients with schizophrenia, regardless of previous cannabis use. The age of first admission due to psychosis was lower in both psychotic inpatients groups with cannabis use (M = 26.1, SD = 6.4 in CIP and M = 25.3, SD = 6.2 in SZ + CB; X² = 20.02, p < 0,001). A clinical pattern characteristic of cannabis-induced psychosis was not observed, but the precipitating role of cannabis in the appearance of psychotic symptoms was demonstrated, given the lower age of first admission due to psychosis in cannabis user groups.