Objective:Reduced motivation is often noted as a consequence of cannabis use. However, previous work has yielded mixed results and focused largely on adults. To address these limitations, this study examined longitudinal associations between cannabis use and self-reported motivation in a large adolescent sample.Method:Participants were 401 adolescents aged 14–17 at baseline who completed five bi-annual assessments. We assessed motivation at three timepoints using two self-report questionnaires: the Apathy Evaluation Scale and the Motivation and Engagement Scale (disengagement, persistence, planning, self-efficacy, and valuing school subscales). Controlling for relevant covariates, we used latent growth curve modeling to characterize patterns of cannabis use and motivation over time, examining bidirectional influences between these processes.Results:On average, adolescent cannabis use frequency increased significantly over time. The disengagement and planning facets of motivation also increased significantly over time, whereas other aspects of motivation remained stable. At baseline, greater cannabis use was associated with greater disengagement, lower planning, and lower valuing of school. Greater baseline cannabis use also predicted lesser increases in disengagement over time. After controlling for the effect of sex, age, depression, and use of alcohol and nicotine, only the baseline association between cannabis use and valuing school remained significant.Conclusions:Our results do not support a prospective link between cannabis use and reduced motivation among adolescents. Although most observed associations were accounted for by covariates, greater cannabis use was cross-sectionally associated with lower perceived value of school, which may contribute to poorer educational and later life outcomes.

中文翻译：

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大麻使用者懈怠缺乏证据：对青少年大麻使用和动机升级的纵向分析

目的：由于使用大麻，人们经常注意到动机降低。然而，以前的工作产生了喜忧参半的结果，主要集中在成年人身上。为了解决这些限制，本研究在一个大型青少年样本中检查了大麻使用与自我报告动机之间的纵向关联。方法：参与者是 401 名基线年龄在 14-17 岁的青少年，他们完成了五次半年度评估。我们使用两个自我报告问卷在三个时间点评估了动机：冷漠评估量表和动机与参与量表（脱离接触、坚持、计划、自我效能和重视学校分量表）。控制相关协变量，我们使用潜在生长曲线模型来描述大麻使用和动机随时间变化的模式，检查这些过程之间的双向影响。结果：平均而言，青少年大麻的使用频率随时间显着增加。随着时间的推移，动机的脱离和计划方面也显着增加，而动机的其他方面则保持稳定。在基线时，更多的大麻使用与更大的脱离接触、更低的规划和更低的学校价值相关。随着时间的推移，更多的基线大麻使用也预示着脱离接触的增加会减少。在控制了性别、年龄、抑郁以及酒精和尼古丁使用的影响后，只有大麻使用与重视学校之间的基线关联仍然显着。结论：我们的结果不支持大麻使用与青少年动机降低之间的前瞻性联系. 尽管大多数观察到的关联是由协变量解释的，