Causal Pathways to Substance use and Dependence in Young People

吸毒？烟草、酒精和大麻--在英国年轻人中依赖的现象很普遍。在16-19岁的年轻人中，四分之一以上的人吸烟；近五分之二的人酗酒；十分之一的人经常吸食大麻。青少年药物使用与教育成绩差和反社会行为有关；成年初期有心理问题；成年后可能导致持续大量饮酒和吸烟，以及随后出现与健康有关的重大问题。青少年吸毒并不是单一的原因。潜在的风险包括孕期和儿童期母亲使用药物、家庭被剥夺以及儿童早期的心理和行为问题。需要更多的证据来梳理出这些多重因素的潜在贡献，以便支持当前和未来的预防战略。这将需要关于物质使用前的早期生活的详细信息，以及关于物质使用在青春期如何发展的信息。物质使用的模式也以各种方式进行了定义，但至今没有一个明确的定义。1991年至2002年招募的ALSPAC队列提供了最好的机会，帮助我们了解英国青少年使用药物的不同轨迹，了解最有可能导致青少年使用和依赖药物的原因，以及药物使用对不良青少年结果的影响。首先，我们将估计17-18岁的药物使用和依赖的流行率(烟草、大麻和酒精分别使用和依赖，并综合衡量)。然后我们将确定不同的物质使用轨迹。其次，我们将在分析中使用这些物质使用轨迹来测试最有可能的因果路径。也就是说，我们将测试一系列因素是否直接或间接(通过它们对其他因素的影响)影响青少年使用药物的模式，包括怀孕期间母亲使用药物、儿童多动症和行为障碍、父母使用药物、剥夺、开始使用药物的年龄以及与大麻代谢相关的基因的影响。第三，我们将检查不同的药物使用轨迹对不良青少年结果的影响(教育成绩差、反社会行为、药物依赖和其他药物使用)。我们将测试物质使用在多大程度上与这些结果有直接或间接的因果联系。最后，我们将为未来的基因研究和开发有效的干预措施提供信息。

Substance use ? tobacco, alcohol and cannabis - and dependence among young people in the UK is widespread. Among young people aged 16-19 over one in four will smoke tobacco; nearly two in five will drink hazardously; one in ten will be regular cannabis smokers. Adolescent substance use is associated with poor educational achievement and antisocial behaviour; psychological problems in early adulthood; and may lead to persistent heavy drinking and smoking in adulthood and the subsequent substantial health related problems. There is no single cause of adolescent substance use. Potential risks include maternal substance use during pregnancy and childhood, family deprivation, and psychological and behavioural problems in early childhood. More evidence is required to tease out the potential contribution of these multiple factors in order to support current and future prevention strategies. This will require detailed information on early life, before substance use, as well as information on how substance use develops during adolescence. Patterns of substance use also have been defined in a variety of ways without a clear definition emerging to date. The ALSPAC cohort, recruited 1991-2, provides the best opportunity to contribute to our understanding of the different trajectories of substance use in adolescents in the UK, on what are the most likely causal pathways leading to substance use and dependence in young people, and on the impact of substance use on adverse adolescent outcomes. Firstly, we will estimate the prevalence of substance use and dependence (separately for tobacco, cannabis and alcohol, and for a combined measure) at age 17-18. We will then identify different trajectories of substance use. Secondly, we will use these substance use trajectories in analyses to test what causal pathways are the most likely. That is, we will test whether a series of factors contribute directly or indirectly (through their impact on other factors) to pattenrs of adolescent substance use, including the influence of maternal substance use whilst pregnant, ADHD and conduct disorder in childhood, parental substance use, deprivation, age starting drug use, and genes associated with cannabis metabolism.Thirdly, we will examine the impact of different substance use trajectories on adverse adolescent outcomes (poor educational performance, antisocial behaviour, substance dependence, and other drug use). We will test the extent to which substance use has a direct or indirect causal link to these outcomes. Finally, we will provide information for future genetic research and for development of effective interventions.