Jacobsen Leslie K, Pugh Kenneth R, Constable Robert T, Westerveld Michael, Mencl W Einar
Department of Psychiatry, Yale University School of Medicine, Connecticut 06519, USA.
Biol Psychiatry. 2007 Jan 1;61(1):31-40. doi: 10.1016/j.biopsych.2006.02.014. Epub 2006 Apr 21.
Cannabis remains the most widely used illicit substance by adolescents and is typically consumed by this population in the context of ongoing tobacco use. Human studies have shown that both cannabis and tobacco exert effects on cognitive function; however, little is known about possible interacting effects of these drugs on brain function and cognition during adolescent development.
Verbal learning and memory were assessed in 20 adolescent users of tobacco and cannabis and 25 adolescent tobacco users with minimal history of cannabis use. Functional magnetic resonance imaging was used to examine brain function and functional connectivity while a subset of these subjects performed a verbal working memory task.
Delayed recall of verbal stimuli deteriorated during nicotine withdrawal among cannabis users but not among comparison subjects. During high verbal working memory load, nicotine withdrawal selectively increased task-related activation of posterior cortical regions and was associated with disruption of frontoparietal connectivity in adolescent cannabis users relative to comparison subjects.
These observations suggest that cannabis use during adolescent development may disrupt neurocircuitry supporting verbal memory formation and that deficits associated with disruption of these neurocircuits are unmasked during nicotine withdrawal.
大麻仍然是青少年使用最广泛的非法物质，并且该人群通常在持续吸烟的情况下使用大麻。人体研究表明，大麻和烟草都会对认知功能产生影响；然而，对于这些药物在青少年发育过程中对脑功能和认知的可能相互作用影响知之甚少。
对20名同时使用烟草和大麻的青少年使用者以及25名大麻使用史极少的青少年烟草使用者进行了言语学习和记忆评估。当这些受试者中的一部分执行言语工作记忆任务时，使用功能磁共振成像来检查脑功能和功能连接性。
大麻使用者在尼古丁戒断期间言语刺激的延迟回忆能力下降，而对照组受试者则未出现这种情况。在高言语工作记忆负荷期间，尼古丁戒断选择性地增加了青少年大麻使用者相对于对照组受试者后皮质区域与任务相关的激活，并与额顶叶连接的中断有关。
这些观察结果表明，青少年发育期间使用大麻可能会破坏支持言语记忆形成的神经回路，并且在尼古丁戒断期间，与这些神经回路破坏相关的缺陷会显现出来。
