Study register · detailProspektive Kohortenstudie · Adolescence & Development · 2018
Adolescent cannabis use, baseline prodromal symptoms and the risk of psychosis.
Mustonen et al.·The British Journal of Psychiatry
Clear benefitGRADEModerate95 citations
Samplen = 6.534 Pat.
DurationFollow-up until age 30 years
ControlNo or rare cannabis use
EndpointPsychosis risk
Blindingn.a.
DesignProspektive Kohortenstudie
”Key finding
Frequent cannabis use in adolescence significantly increases the risk of psychosis even after controlling for relevant confounders (HR=3,0).
Summary
Adolescent cannabis use (age 15–16 years, ≥5 times) in prospective cohort (n=6.534) associated with >3-fold increased psychosis risk up to age 30 after adjustment (HR=3,0, 95% CI 1,1–8,0); onset before the 17th year of life identified as risk modifier.
P
PopulationJugendliche aus der allgemeinen Bevölkerung (Nordfinnland-Geburtskohorte 1986), n=6534, Alter 15–16 Jahre zu Baseline
I
InterventionCannabis use in adolescence (≥5-fold use up to age 15–16 years)
C
ControlNo or rare cannabis use
O
OutcomeIncreased psychosis risk with ≥5-fold cannabis use (HR=6,5; 95%-CI 3,0–13,9); after adjustment for prodromal symptoms, other substance use and parental psychosis still significant (HR=3,0; 95%-CI 1,1–8,0)
Confidence in the evidence
Very lowLowModerateHigh
Moderate
The third of four GRADE levels, the effect estimate is probably reliable.
Quality profile
Sample size★★★★★
Blinding—
Effect sizeClear benefit
Citations / year★★★★★
Authors
Mustonen A, Niemelä S, Nordström T, Murray GK, Mäki P, Jääskeläinen E, Miettunen J.
<h4>Background</h4>The association between cannabis use and the risk of psychosis has been studied extensively but the temporal order still remains controversial. Aims To examine the association between cannabis use in adolescence and the risk of psychosis after adjustment for prodromal symptoms and other potential confounders.<h4>Method</h4>The sample (n = 6534) was composed of the prospective general population-based Northern Finland Birth Cohort of 1986. Information on prodromal symptoms of psychosis and cannabis use was collected using questionnaires at age 15-16 years. Participants were followed up for ICD-10 psychotic disorders until age 30 years using nationwide registers.<h4>Results</h4>The risk of psychosis was elevated in individuals who had tried cannabis five times or more (hazard ratio, (HR) = 6.5, 95% CI 3.0-13.9). The association remained statistically significant even when adjusted for prodromal symptoms, other substance use and parental psychosis (HR = 3.0, 95% CI 1.1-8.0).<h4>Conclusions</h4>Adolescent cannabis use is associated with increased risk of psychosis even after adjustment for baseline prodromal symptoms, parental psychosis and other substance use. Declaration of interest None.