Abstract Objective: Shifting policies and widespread acceptance of cannabis for medical and/or recreational purposes have fueled worries of increased cannabis initiation and use in adolescents. In particular, the adolescent period is thought to be associated with an increased susceptibility to the potential harms of repeated cannabis use, due to being a critical period for neuromaturational events in the brain. This review investigates the neuroimaging evidence of brain harms attributable to adolescent cannabis use. Methods: PubMed and Scopus searches were conducted for empirical articles that examined neuroimaging effects in both adolescent cannabis users and adult user studies that explored the effect of age at cannabis use onset on the brain. Results: We found 43 studies that examined brain effect (structural and functional magnetic resonance imaging) in adolescent cannabis users and 20 that examined the link between onset age of cannabis use and brain effects in adult users. Studies on adolescent cannabis users relative to nonusers mainly implicate frontal and parietal regions and associated brain activation in relation to inhibitory control, reward, and memory. However, studies in adults are more mixed, many of which did not observe an effect of onset age of cannabis use on brain imaging metrics. Conclusions: While there is some evidence of compromised frontoparietal structure and function in adolescent cannabis use, it remains unclear whether the observed effects are specifically attributable to adolescent onset of use or general cannabis use–related factors such as depressive symptoms. The relative contribution of adolescent onset of cannabis use and use chronicity will have to be more comprehensively examined in prospective, longitudinal studies with more rigorous measures of cannabis use (dosage, exposure, dependence, constituent compounds such as the relative cannabinoid levels).

中文翻译：

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大麻在青春期的使用：神经影像学研究结果回顾

摘要 目的：出于医疗和/或娱乐目的，不断变化的政策和对大麻的广泛接受加剧了对青少年吸食和使用大麻增加的担忧。特别是，青少年时期被认为与反复使用大麻的潜在危害的易感性增加有关，因为这是大脑神经成熟事件的关键时期。本综述调查了可归因于青少年大麻使用的大脑伤害的神经影像学证据。方法：PubMed 和 Scopus 搜索了实证文章，这些文章检查了青少年大麻使用者和成人使用者研究中神经影像学的影响，这些研究探讨了年龄对大麻使用开始对大脑的影响。结果：我们发现 43 项研究检查了青少年大麻使用者的大脑效应（结构和功能磁共振成像），还有 20 项研究检查了大麻使用的起始年龄与成年使用者大脑效应之间的联系。对青少年大麻使用者相对于非使用者的研究主要涉及与抑制控制、奖励和记忆相关的额叶和顶叶区域以及相关的大脑激活。然而，对成年人的研究更加复杂，其中许多没有观察到大麻使用的起始年龄对大脑成像指标的影响。结论：虽然有一些证据表明青少年使用大麻时额顶结构和功能受损，但尚不清楚观察到的影响是否具体归因于青少年使用大麻或与一般大麻使用相关的因素，如抑郁症状。