McGrath John, Welham Joy, Scott James, Varghese Daniel, Degenhardt Louisa, Hayatbakhsh Mohammad Reza, Alati Rosa, Williams Gail M, Bor William, Najman Jake M
Queensland Brain Institute, University of Queensland, St Lucia, Queensland, Australia.
Arch Gen Psychiatry. 2010 May;67(5):440-7. doi: 10.1001/archgenpsychiatry.2010.6. Epub 2010 Mar 1.
Prospective cohort studies have identified an association between cannabis use and later psychosis-related outcomes, but concerns remain about unmeasured confounding variables. The use of sibling pair analysis reduces the influence of unmeasured residual confounding.
To explore the association between cannabis use and psychosis-related outcomes.
A sibling pair analysis nested within a prospective birth cohort.
Births at a Brisbane, Australia, hospital.
Three thousand eight hundred one young adults born between 1981 and 1984 as part of the Mater-University Study of Pregnancy.
Cannabis use and 3 psychosis-related outcomes (nonaffective psychosis, hallucinations, and Peters et al Delusions Inventory score) were assessed at the 21-year follow-up. Associations between duration since first cannabis use and psychosis-related outcomes were examined using logistic regression adjusted for sex, age, parental mental illness, and hallucinations at the 14-year follow-up. Within 228 sibling pairs, the association between within-pair differences in duration since first cannabis use and Peters et al Delusions Inventory score was examined with general linear modeling. The potential impact of attrition was examined.
Duration since first cannabis use was associated with all 3 psychosis-related outcomes. For those with duration since first cannabis use of 6 or more years, there was a significantly increased risk of (1) nonaffective psychosis (adjusted odds ratio, 2.2; 95% confidence interval, 1.1-4.5), (2) being in the highest quartile of Peters et al Delusions Inventory score (adjusted odds ratio, 4.2; 95% confidence interval, 4.2-5.8), and (3) hallucinations (adjusted odds ratio, 2.8; 95% confidence interval, 1.9-4.1). Within sibling pairs, duration since first cannabis use and higher scores on the Peters et al Delusions Inventory remained significantly associated.
Early cannabis use is associated with psychosis-related outcomes in young adults. The use of sibling pairs reduces the likelihood that unmeasured confounding explains these findings. This study provides further support for the hypothesis that early cannabis use is a risk-modifying factor for psychosis-related outcomes in young adults.
前瞻性队列研究已确定大麻使用与后期精神病相关结局之间存在关联，但对于未测量的混杂变量仍存在担忧。同胞对分析的使用减少了未测量的残余混杂因素的影响。
探讨大麻使用与精神病相关结局之间的关联。
在前瞻性出生队列中进行的同胞对分析。
澳大利亚布里斯班一家医院的出生情况。
作为母亲-大学妊娠研究的一部分，1981年至1984年出生的3801名年轻人。
在21年随访时评估大麻使用情况和3种精神病相关结局（非情感性精神病、幻觉和彼得斯等人的妄想量表得分）。使用逻辑回归分析首次使用大麻后的持续时间与精神病相关结局之间的关联，并对14年随访时的性别、年龄、父母精神疾病和幻觉进行调整。在228对同胞中，使用一般线性模型检查首次使用大麻后的持续时间的配对差异与彼得斯等人的妄想量表得分之间的关联。研究了失访的潜在影响。
首次使用大麻后的持续时间与所有3种精神病相关结局相关。对于首次使用大麻后持续时间为6年或更长时间的人，（1）非情感性精神病的风险显著增加（调整后的优势比，2.2；95%置信区间，1.1 - 4.5），（2）处于彼得斯等人的妄想量表得分最高四分位数的风险显著增加（调整后的优势比，4.2；95%置信区间，4.2 - 5
