Importance There is concern about potentially causal effects of tobacco use on psychosis, but epidemiological studies have been less robust in attempts to minimize effects of confounding than studies of cannabis use have been.

Objectives To examine the association of patterns of cigarette and cannabis use with preceding and subsequent psychotic experiences, and to compare effects of confounding across these patterns.

Design, Setting, and Participants This cohort study used data from the Avon Longitudinal Study of Parents and Children, which initially consisted of 14 062 children. Data were collected periodically from September 6, 1990, with collection ongoing, and analyzed from August 8, 2016, through June 14, 2017. Cigarette and cannabis use data were summarized using longitudinal latent class analysis to identify longitudinal classes of substance use. Associations between classes and psychotic experiences at age 18 years were assessed.

Exposures Depending on the analysis model, exposures were longitudinal classes of substance use or psychotic experiences at age 12 years.

Main Outcomes and Measures Logistic regression was used to examine the associations between substance use longitudinal classes and subsequent onset of psychotic experiences.

Results Longitudinal classes were derived using 5300 participants (56.1% female) who had at least 3 measures of cigarette and cannabis use from ages 14 to 19 years. Prior to adjusting for a range of potential confounders, there was strong evdience that early-onset cigarette-only use (4.3%), early-onset cannabis use (3.2%), and late-onset cannabis use (11.9%) (but not later-onset cigarette-only use [14.8%]) latent classes were associated with increased psychotic experiences compared with nonusers (65.9%) (omnibus P < .001). After adjusting for confounders, the association for early-onset cigarette-only use attenuated substantially (unadjusted odds ratio [OR], 3.03; 95% CI, 1.13-8.14; adjusted OR, 1.78; 95% CI, 0.54-5.88), whereas those for early-onset cannabis use (adjusted OR, 3.70; 95% CI, 1.66-8.25) and late-onset cannabis use (adjusted OR, 2.97; 95% CI, 1.63-5.40) remained consistent.

Conclusions and Relevance In this study, our findings indicate that while individuals who use cannabis or cigarettes during adolescence have an increased risk of subsequent psychotic experiences, epidemiological evidence is substantively more robust for cannabis use than it is for tobacco use.

重要性 人们担心使用烟草对精神病有潜在的因果关系，但是流行病学研究在试图将混杂影响减至最小的努力上不如对大麻的研究那样有力。

目的 研究香烟和大麻使用方式与先前和之后的精神病经历之间的关联，并比较这些方式之间混淆的影响。

设计，环境和参与者 本队列研究使用了雅芳父母和孩子纵向研究的数据，该研究最初由14 062名儿童组成。从1990年9月6日开始定期收集数据，并进行收集，并从2016年8月8日到2017年6月14日进行分析。使用纵向潜在类别分析汇总了香烟和大麻使用数据，以识别物质使用的纵向类别。评估了18岁时班级与精神病经历之间的关联。

暴露 根据分析模型的不同，暴露是指12岁时物质使用或精神病经历的纵向分类。

主要结果和测量 方法采用Logistic回归分析物质使用纵向分类与随后的精神病发作之间的联系。

结果 纵向分类是由5300名参与者（56.1％的女性）得出的，他们在14至19岁之间至少有3种香烟和大麻使用量。在对一系列潜在的混杂因素进行调整之前，有强烈的证据表明，仅早期吸烟（4.3％），早期大麻使用（3.2％）和晚期大麻使用（11.9％）（但不是）与非使用者相比（65.9％），较晚发作的仅使用香烟[14.8％]）潜伏类别与增加的精神病经历有关（综合P <.001）。在对混杂因素进行调整之后，仅用于早期发作的吸烟的关联性显着减弱（未调整的优势比[OR]，3.03； 95％CI，1.13-8.14；调整后的OR，1.78； 95％CI，0.54-5.88），而早发性大麻使用（调整后的OR，3.70； 95％CI，1.66-8.25）和晚发性大麻使用（调整后的OR，2.97； 95％CI，1.63-5.40）保持一致。

结论与相关性 在这项研究中，我们的发现表明，虽然在青春期使用大麻或香烟的人发生随后的精神病经历的风险增加，但流行病学证据对大麻的使用实质上比对烟草的使用更为有效。