OBJECTIVE Examine the nature of the relationship between adolescent polysubstance use and high school noncompletion. METHOD Among a sample of 9,579 adult Australian twins (58.63% female, Mage = 30.59), we examined the association between the number of substances used in adolescence and high school noncompletion within a discordant twin design and bivariate twin analysis. RESULTS In individual-level models controlling for parental education, conduct disorder symptoms, childhood major depression, sex, zygosity, and cohort, each additional substance used in adolescence was associated with a 30% increase in the odds of high school noncompletion (OR = 1.30 [1.18, 1.42]). Discordant twin models found that the potentially causal effect of adolescent use on high school noncompletion was nonsignificant (OR = 1.19 [0.96, 1.47]). Follow-up bivariate twin models suggested genetic (35.4%, 95% CI [24.5%, 48.7%]) and shared environmental influences (27.8%, 95% CI [12.7%, 35.1%]) each contributed to the covariation in adolescent polysubstance use and early school dropout. CONCLUSIONS The association between polysubstance use and early school dropout was largely accounted for by genetic and shared environmental factors, with nonsignificant evidence for a potentially causal association. Future research should examine whether underlying shared risk factors reflect a general propensity for addiction, a broader externalizing liability, or a combination of the two. More evidence using finer measurement of substance use is needed to rule out a causal association between adolescent polysubstance use and high school noncompletion. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

中文翻译：

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遗传和共同的环境因素解释了青少年使用多种物质与高中未完成学业之间的关联。

目的 探讨青少年多物质使用与高中未完成学业之间关系的本质。方法 在 9,579 名澳大利亚成年双胞胎（58.63% 为女性，Mage = 30.59）样本中，我们通过不一致双胞胎设计和双变量双胞胎分析，研究了青春期使用的物质数量与高中未完成学业之间的关联。结果 在控制了父母教育、品行障碍症状、儿童重度抑郁症、性别、合子性和队列的个体水平模型中，青春期使用的每一种额外物质都与高中未完成学业的几率增加 30% 相关（OR = 1.30） [1.18，1.42]）。不一致的双胞胎模型发现，青少年使用药物对高中未完成学业的潜在因果影响并不显着（OR = 1.19 [0.96, 1.47]）。随访双变量双胞胎模型表明，遗传（35.4％，95％CI [24.5％，48.7％]）和共同的环境影响（27.8％，95％CI [12.7％，35.1％]）各自导致青少年多物质的共变使用和早期辍学。结论 多种物质使用与早期辍学之间的关联很大程度上是由遗传和共同的环境因素造成的，没有证据表明存在潜在的因果关系。未来的研究应该考察潜在的共同风险因素是否反映了普遍的成瘾倾向、更广泛的外化责任，或者两者的结合。需要更多证据使用更精细的物质使用测量来排除青少年多种物质使用与高中未完成学业之间的因果关系。（PsycInfo 数据库记录 (c) 2023 APA，保留所有权利）。