School of Psychology, University of Wollongong, Northfields Ave, Wollongong, NSW, 2522, Australia.
Psychopharmacology (Berl). 2011 Jul;216(1):131-44. doi: 10.1007/s00213-011-2203-x. Epub 2011 Feb 17.
Long-term heavy cannabis use can result in memory impairment. Adolescent users may be especially vulnerable to the adverse neurocognitive effects of cannabis.
In a cross-sectional and prospective neuropsychological study of 181 adolescents aged 16-20 (mean 18.3 years), we compared performance indices from one of the most widely used measures of learning and memory--the Rey Auditory Verbal Learning Test--between cannabis users (n=52; mean 2.4 years of use, 14 days/month, median abstinence 20.3 h), alcohol users (n=67) and non-user controls (n=62) matched for age, education and premorbid intellectual ability (assessed prospectively), and alcohol consumption for cannabis and alcohol users.
Cannabis users performed significantly worse than alcohol users and non-users on all performance indices. They recalled significantly fewer words overall (p<0.001), demonstrating impaired learning (p<0.001), retention (p<0.001) and retrieval (p<0.05) (Cohen's d 0.43-0.84). The degree of impairment was associated with the duration, quantity, frequency and age of onset of cannabis use, but was unrelated to alcohol exposure or other drug use. No gender effects were detected and the findings remained after controlling for premorbid intellectual ability. An earlier age of onset of regular cannabis use was associated with worse memory performance after controlling for extent of exposure to cannabis.
Despite relatively brief exposure, adolescent cannabis users relative to their age-matched counterparts demonstrated similar memory deficits to those reported in adult long-term heavy users. The results indicate that cannabis adversely affects the developing brain and reinforce concerns regarding the impact of early exposure.
长期大量使用大麻可导致记忆力下降。青少年使用者可能尤其容易受到大麻对神经认知的负面影响。
在一项针对 181 名 16-20 岁青少年（平均 18.3 岁）的横断面和前瞻性神经心理学研究中，我们比较了使用最广泛的学习和记忆测试之一—— Rey 听觉言语学习测试（Rey Auditory Verbal Learning Test）的各项表现指标，比较对象为大麻使用者（n=52；使用大麻 2.4 年，每月 14 天，中位戒断时间 20.3 小时）、酒精使用者（n=67）和年龄、教育程度和潜在智力能力相匹配的非使用者对照（n=62）（前瞻性评估），以及大麻和酒精使用者的酒精摄入量。
与酒精使用者和非使用者相比，大麻使用者在所有表现指标上均显著较差。他们总体上回忆的单词明显较少（p<0.001），表现出学习（p<0.001）、保持（p<0.001）和检索（p<0.05）的缺陷（Cohen's d 0.43-0.84）。损伤程度与大麻使用的持续时间、数量、频率和发病年龄有关，但与酒精暴露或其他药物使用无关。未检测到性别影响，并且在控制潜在智力能力后，发现仍然存在。在控制大麻接触程度后，较早开始定期使用大麻与记忆表现较差有关。
尽管暴露时间相对较短，但与年龄匹配的对照者相比，青少年大麻使用者表现出与成年长期大量使用者类似的记忆缺陷。结果表明大麻对发育中的大脑有不良影响，并强化了对早期暴露影响的担忧。
