Curran H Valerie, Brignell Catherine, Fletcher Sally, Middleton Paul, Henry John
Psychopharmacology Laboratories, Clinical Health Psychology, University College London, Gower Street, London WC1 6BT, UK.
Psychopharmacology (Berl). 2002 Oct;164(1):61-70. doi: 10.1007/s00213-002-1169-0. Epub 2002 Jul 23.
Although some aspects of memory functions are known to be acutely impaired by delta(9)-tetrahydrocannabinol (delta(9)-THC; the main active constituent of marijuana), effects on other aspects of memory are not known and the time course of functional impairments is unclear.
The present study aimed to detail the acute and residual cognitive effects of delta(9)-THC in infrequent cannabis users.
A balanced, double-blind cross-over design was used to compare the effects of 7.5 mg and 15 mg delta(9)-THC with matched placebo in 15 male volunteers. Participants were assessed pre and 1, 2, 4, 6, 8, 24 and 48 h post-drug.
Delta(9)-THC 15 mg impaired performance on two explicit memory tasks at the time of peak plasma concentration (2 h post-drug). At the same time point, performance on an implicit memory task was preserved intact. The higher dose of delta(9)-THC resulted in no learning whatsoever occurring over a three-trial selective reminding task at 2 h. Working memory was generally unaffected by delta(9)-THC. In several tasks, delta(9)-THC increased both speed and error rates, reflecting "riskier" speed-accuracy trade-offs. Subjective effects were also most marked at 2 h but often persisted longer, with participants rating themselves as "stoned" for 8 h. Participants experienced a strong drug effect, liked this effect and, until 4 h, wanted more oral delta(9)-THC. No effects of delta(9)-THC were found 24 or 48 h following ingestion indicating that the residual effects of oral delta(9)-THC are minimal.
These data demonstrate that oral delta(9)-THC impairs episodic memory and learning in a dose-dependent manner whilst sparing perceptual priming and working memory.
虽然已知记忆功能的某些方面会受到δ9 - 四氢大麻酚（δ9 - THC；大麻的主要活性成分）的急性损害，但对记忆其他方面的影响尚不清楚，且功能损害的时间进程也不明确。
本研究旨在详细阐述δ9 - THC对不常使用大麻者的急性和残留认知影响。
采用平衡、双盲交叉设计，比较15名男性志愿者服用7.5毫克和15毫克δ9 - THC与匹配安慰剂的效果。在用药前以及用药后1、2、4、6、8、24和48小时对参与者进行评估。
服用15毫克δ9 - THC后，在血浆浓度峰值时（用药后2小时），两项外显记忆任务的表现受损。在同一时间点，内隐记忆任务的表现保持完好。较高剂量的δ9 - THC导致在2小时的三次试验选择性提醒任务中未发生任何学习。工作记忆一般不受δ9 - THC影响。在多项任务中，δ9 - THC提高了速度和错误率，反映出“更冒险”的速度 - 准确性权衡。主观效应在2小时时也最为明显，但通常持续时间更长，参与者在8小时内将自己评为“飘飘然”。参与者体验到强烈的药物效应，喜欢这种效应，并且在4小时之前想要更多的口服δ9 - THC。摄入后24或48小时未发现δ9 - THC有任何影响，表明口服δ9 - THC的残留效应极小。
这些数据表明，口服δ9 - THC以剂量依赖的方式损害情景记忆和学习，同时不影响知觉启动和工作记忆。
