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Study register · detail Prospektive Kohortenstudie · Psychosis Risk · 1994

Cannabis abuse and the course of recent-onset schizophrenic disorders.

Linszen et al. ·Archives of General Psychiatry
Harm GRADE Very low 668 citations
Samplen = 93 Pat.
Duration1 year
ControlNo cannabis abuse
EndpointBPRS
Blindingn.a.
DesignProspektive Kohortenstudie
Key finding

Cannabis abuse significantly increases the risk of psychotic relapses in schizophrenia, more pronounced dose-dependently with severe abuse.

Summary

Prospective 1-year cohort study (n=93: 24 cannabis users vs. 69 non-users) in patients with early-onset schizophrenia. Significantly more and earlier psychotic relapses in the cannabis group (p=0,03); association stronger with severe use (p=0,002). No confounding by other drugs. In all but one patient, cannabis use preceded the first psychotic symptom by >1 year.

P
PopulationPatients with recently begun schizophrenia-spectrum disorder, n=93 (24 cannabis abusers, 69 non-abusers)
I
InterventionCannabis abuse (mild n=11, severe n=13) – naturalistically observed
C
ControlNo cannabis abuse (n=69)
O
OutcomeSignificantly more and earlier psychotic relapses in the cannabis group (p=0,03); stronger with severe abuse (p=0,002)
Confidence in the evidence
Very low

The lowest GRADE level, the effect estimate remains uncertain.

Downgraded for
Imprecision
Quality profile
Sample size ★★★★★
Blinding —
Effect size Harm
Citations / year ★★★★★
Authors
Linszen DH, Dingemans PM, Lenior ME.
DOI 10.1001/archpsyc.1994.03950040017002↗
Design: Prospektive Kohortenstudie
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Abstract
<h4>Objective</h4>We sought to examine the relation between cannabis abuse and the symptomatic course of recent-onset schizophrenia and related disorders.<h4>Design</h4>A prospective cohort study over a year using monthly Brief Psychiatric Rating Scale assessments.<h4>Participants</h4>Cannabis-abusing patients (n = 24) were compared with nonabusers (n = 69). Eleven patients were mild and 13 were heavy cannabis-abusing patients.<h4>Results</h4>Significantly more and earlier psychotic relapses occurred in the cannabis-abusing group (P = .03). This association became stronger when mild and heavy cannabis abuse were distinguished (P = .002). No confounding effect of other variables, eg, other street drugs, was found. In all but one patient, cannabis abuse preceded the onset of the first psychotic symptoms for at least 1 year.<h4>Conclusions</h4>Cannabis abuse and particularly heavy abuse can be considered a stressor eliciting relapse in patients with schizophrenia and related disorders and possibly a premorbid precipitant.
Indication
Further studies on Psychosis Risk
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The impediment to action advances action. — Marcus Aurelius