Department of Psychology and Neuroscience, Duke University, Durham, NC 27708, USA.
Proc Natl Acad Sci U S A. 2012 Oct 2;109(40):E2657-64. doi: 10.1073/pnas.1206820109. Epub 2012 Aug 27.
Recent reports show that fewer adolescents believe that regular cannabis use is harmful to health. Concomitantly, adolescents are initiating cannabis use at younger ages, and more adolescents are using cannabis on a daily basis. The purpose of the present study was to test the association between persistent cannabis use and neuropsychological decline and determine whether decline is concentrated among adolescent-onset cannabis users. Participants were members of the Dunedin Study, a prospective study of a birth cohort of 1,037 individuals followed from birth (1972/1973) to age 38 y. Cannabis use was ascertained in interviews at ages 18, 21, 26, 32, and 38 y. Neuropsychological testing was conducted at age 13 y, before initiation of cannabis use, and again at age 38 y, after a pattern of persistent cannabis use had developed. Persistent cannabis use was associated with neuropsychological decline broadly across domains of functioning, even after controlling for years of education. Informants also reported noticing more cognitive problems for persistent cannabis users. Impairment was concentrated among adolescent-onset cannabis users, with more persistent use associated with greater decline. Further, cessation of cannabis use did not fully restore neuropsychological functioning among adolescent-onset cannabis users. Findings are suggestive of a neurotoxic effect of cannabis on the adolescent brain and highlight the importance of prevention and policy efforts targeting adolescents.
最近的报告显示，越来越少的青少年认为经常使用大麻对健康有害。与此同时，青少年开始使用大麻的年龄越来越小，每天使用大麻的青少年也越来越多。本研究的目的是检验持续使用大麻与神经认知能力下降之间的关联，并确定下降是否集中在青少年开始使用大麻的人群中。参与者是达尼丁研究的成员，这是一项对 1037 名出生队列个体进行的前瞻性研究，从出生（1972/1973 年）开始跟踪到 38 岁。大麻使用情况在参与者 18、21、26、32 和 38 岁时的访谈中确定。神经心理学测试在 13 岁时进行，即在开始使用大麻之前进行，然后在 38 岁时再次进行，此时已经形成了持续使用大麻的模式。即使控制了受教育年限，持续使用大麻也与广泛的认知功能领域的神经认知能力下降有关。报告人还报告说，他们注意到持续使用大麻的人认知问题更多。损伤主要集中在青少年开始使用大麻的人群中，持续使用量越大，下降幅度越大。此外，青少年开始使用大麻后停止使用大麻并不能完全恢复他们的神经认知功能。研究结果提示大麻对青少年大脑有神经毒性作用，并强调了针对青少年的预防和政策努力的重要性。
