Dose-related Neurocognitive Effects of Marijuana Use

背景：尽管美国约有700万人每周至少吸食一次大麻，但有关吸食大麻对神经认知的持续影响的科学数据很少。目的：确定戒断28天的大量大麻使用者是否存在神经认知缺陷，以及这些缺陷是否与每周吸食大麻的数量有关。方法：对戒毒28天的重度大麻滥用者进行一系列神经认知测试。结果：随着关节每周吸烟次数的增加，在测试记忆力、执行功能、精神运动速度和手动灵活性方面的表现有所下降。当将受试者分为轻度、中度和重度使用者组时，重度使用者组在35项测量中有5项的表现明显低于轻度使用者组，影响的大小从3.00到4.20 SD单位不等。使用时间对神经认知表现几乎没有影响。结论：即使在戒烟28天后，大量使用大麻也与神经认知能力的持续下降有关。目前尚不清楚，这些减少是会随着持续的戒烟而解决，还是会随着继续大量使用大麻而变得越来越糟。

BACKGROUND: Although about 7 million people in the US population use marijuana at least weekly, there is a paucity of scientific data on persistent neurocognitive effects of marijuana use. OBJECTIVE: To determine if neurocognitive deficits persist in 28-day abstinent heavy marijuana users and if these deficits are dose-related to the number of marijuana joints smoked per week. METHODS: A battery of neurocognitive tests was given to 28-day abstinent heavy marijuana abusers. RESULTS: As joints smoked per week increased, performance decreased on tests measuring memory, executive functioning, psychomotor speed, and manual dexterity. When dividing the group into light, middle, and heavy user groups, the heavy group performed significantly below the light group on 5 of 35 measures and the size of the effect ranged from 3.00 to 4.20 SD units. Duration of use had little effect on neurocognitive performance. CONCLUSIONS: Very heavy use of marijuana is associated with persistent decrements in neurocognitive performance even after 28 days of abstinence. It is unclear if these decrements will resolve with continued abstinence or become progressively worse with continued heavy marijuana use.