Fried P A, Watkinson B, Gray R
Department of Psychology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6.
Neurotoxicol Teratol. 2005 Mar-Apr;27(2):231-9. doi: 10.1016/j.ntt.2004.11.003. Epub 2004 Dec 9.
In determining the effects of regular marihuana use on neurocognition, abilities within specific relevant cognitive domains prior to regular drug use have not been available. The present study examined effects of current and past regular use of marihuana in subjects for whom pre-drug performance had been ascertained in a prospective, longitudinal fashion. A total of 113 young adults, assessed since infancy, were evaluated using neurocognitive tests for which commensurate measures were obtained prior to the initiation of marihuana smoking. Marihuana users, determined by urinalysis and self-report, were categorized as light (< 5 joints per week) and heavy (> or = 5 joints per week) current users and former users, the latter having used the drug regularly in the past (> or = 1 joint per week) but not for at least 3 months. A third of the subjects were using marihuana on a regular basis at the time of assessment with half being heavy users. Among former, regular users, approximately half had been smoking 5 or more joints per week. Overall IQ, memory, processing speed, vocabulary, attention, and abstract reasoning were assessed. After accounting for potentially confounding factors and pre-drug performance in the appropriate cognitive domain, current regular heavy users did significantly worse than non-users in overall IQ, processing speed, immediate, and delayed memory. In contrast, the former marihuana smokers did not show any cognitive impairments. It was concluded that residual marihuana effects are evident beyond the acute intoxication period in current heavy users after taking into account pre-drug performance but similar deficits are no longer apparent 3 months after cessation of regular use, even among former heavy using young adults.
在确定长期使用大麻对神经认知的影响时，一直缺乏定期吸毒之前特定相关认知领域内的能力数据。本研究考察了大麻当前和过去的长期使用对那些已通过前瞻性纵向方式确定吸毒前表现的受试者的影响。共有113名自婴儿期起就接受评估的年轻人，使用神经认知测试进行了评估，这些测试在开始吸食大麻之前就已获得相应的测量值。通过尿液分析和自我报告确定的大麻使用者被分为轻度（每周少于5支大麻烟）和重度（每周5支或更多大麻烟）当前使用者以及既往使用者，后者过去曾定期使用该药物（每周1支或更多）但至少3个月未使用。三分之一的受试者在评估时正在定期使用大麻，其中一半是重度使用者。既往定期使用者中，约一半每周吸食5支或更多大麻烟。评估了总体智商、记忆力、处理速度、词汇量、注意力和抽象推理能力。在考虑了潜在的混杂因素以及在适当认知领域的吸毒前表现后，当前定期重度使用者在总体智商、处理速度、即时和延迟记忆方面的表现明显比非使用者差。相比之下，既往吸食大麻者未表现出任何认知障碍。研究得出结论，在考虑吸毒前表现后，当前重度使用者在急性中毒期之后仍存在明显的大麻残留效应，但即使是既往重度使用大麻的年轻成年人，在停止定期使用3个月后，类似的缺陷也不再明显。
