TY - JOUR
T1 - Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users
AU - Di Forti, Marta
AU - Sallis, Hannah
AU - Allegri, Fabio
AU - Trotta, Antonella
AU - Ferraro, Laura
AU - Stilo, Simona A
AU - Marconi, Arianna
AU - La Cascia, Caterina
AU - Reis Marques, Tiago
AU - Pariante, Carmine
AU - Dazzan, Paola
AU - Mondelli, Valeria
AU - Paparelli, Alessandra
AU - Kolliakou, Anna
AU - Prata, Diana
AU - Gaughran, Fiona
AU - David, Anthony S
AU - Morgan, Craig
AU - Stahl, Daniel
AU - Khondoker, Mizanur
AU - MacCabe, James H
AU - Murray, Robin M
N1 - © The Author 2013. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.
PY - 2014/11
Y1 - 2014/11
N2 - UNLABELLED: Cannabis use is associated with an earlier age of onset of psychosis (AOP). However, the reasons for this remain debated.METHODS: We applied a Cox proportional hazards model to 410 first-episode psychosis patients to investigate the association between gender, patterns of cannabis use, and AOP.RESULTS: Patients with a history of cannabis use presented with their first episode of psychosis at a younger age (mean years = 28.2, SD = 8.0; median years = 27.1) than those who never used cannabis (mean years = 31.4, SD = 9.9; median years = 30.0; hazard ratio [HR] = 1.42; 95% CI: 1.16-1.74; P < .001). This association remained significant after controlling for gender (HR = 1.39; 95% CI: 1.11-1.68; P < .001). Those who had started cannabis at age 15 or younger had an earlier onset of psychosis (mean years = 27.0, SD = 6.2; median years = 26.9) than those who had started after 15 years (mean years = 29.1, SD = 8.5; median years = 27.8; HR = 1.40; 95% CI: 1.06-1.84; P = .050). Importantly, subjects who had been using high-potency cannabis (skunk-type) every day had the earliest onset (mean years = 25.2, SD = 6.3; median years = 24.6) compared to never users among all the groups tested (HR = 1.99; 95% CI: 1.50- 2.65; P < .0001); these daily users of high-potency cannabis had an onset an average of 6 years earlier than that of non-cannabis users.CONCLUSIONS: Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users.
AB - UNLABELLED: Cannabis use is associated with an earlier age of onset of psychosis (AOP). However, the reasons for this remain debated.METHODS: We applied a Cox proportional hazards model to 410 first-episode psychosis patients to investigate the association between gender, patterns of cannabis use, and AOP.RESULTS: Patients with a history of cannabis use presented with their first episode of psychosis at a younger age (mean years = 28.2, SD = 8.0; median years = 27.1) than those who never used cannabis (mean years = 31.4, SD = 9.9; median years = 30.0; hazard ratio [HR] = 1.42; 95% CI: 1.16-1.74; P < .001). This association remained significant after controlling for gender (HR = 1.39; 95% CI: 1.11-1.68; P < .001). Those who had started cannabis at age 15 or younger had an earlier onset of psychosis (mean years = 27.0, SD = 6.2; median years = 26.9) than those who had started after 15 years (mean years = 29.1, SD = 8.5; median years = 27.8; HR = 1.40; 95% CI: 1.06-1.84; P = .050). Importantly, subjects who had been using high-potency cannabis (skunk-type) every day had the earliest onset (mean years = 25.2, SD = 6.3; median years = 24.6) compared to never users among all the groups tested (HR = 1.99; 95% CI: 1.50- 2.65; P < .0001); these daily users of high-potency cannabis had an onset an average of 6 years earlier than that of non-cannabis users.CONCLUSIONS: Daily use, especially of high-potency cannabis, drives the earlier onset of psychosis in cannabis users.
U2 - 10.1093/schbul/sbt181
DO - 10.1093/schbul/sbt181
M3 - Article (Academic Journal)
C2 - 24345517
VL - 40
SP - 1509
EP - 1517
JO - Schizophrenia Bulletin
JF - Schizophrenia Bulletin
SN - 0586-7614
IS - 6
ER -