Moeller Scott J, Maloney Thomas, Parvaz Muhammad A, Dunning Jonathan P, Alia-Klein Nelly, Woicik Patricia A, Hajcak Greg, Telang Frank, Wang Gene-Jack, Volkow Nora D, Goldstein Rita Z
Department of Psychology, University of Michigan, Ann Arbor, Michigan 48109, USA.
Biol Psychiatry. 2009 Jul 15;66(2):169-76. doi: 10.1016/j.biopsych.2009.02.015. Epub 2009 Apr 9.
Individuals with cocaine use disorder (CUD) chose cocaine over nondrug rewards. In two newly designed laboratory tasks with pictures, we document this modified choice outside of a cocaine administration paradigm.
Choice for viewing cocaine, pleasant, unpleasant, or neutral pictures--under explicit contingencies (choice made between two fully visible side-by-side images) and under more implicit contingencies (selections made between pictures hidden under flipped-over cards)--was examined in 20 CUD and 20 matched healthy control subjects. Subjects also provided self-reported ratings of each picture's pleasantness and arousal.
Under both contingencies, CUD subjects chose to view more cocaine pictures than control subjects, group differences that were not fully explained by the self-reported picture ratings. Furthermore, whereas CUD subjects' choice for viewing cocaine pictures exceeded choice for viewing unpleasant pictures (but did not exceed choice for viewing pleasant pictures, in contrast to their self-reported ratings), healthy control subjects avoided viewing cocaine pictures as frequently as, or even more than, unpleasant pictures. Finally, CUD subjects with the most cocaine viewing selections, even when directly compared with selections of the pleasant pictures, also reported the most frequent recent cocaine use.
Enhanced drug-related choice in cocaine addiction can be demonstrated even for nonpharmacologic (pictorial) stimuli. This choice, which is modulated by alternative stimuli, partly transcends self-reports (possibly indicative of a disconnect in cocaine addiction between self-reports and objective behavior) to provide an objective marker of addiction severity. Neuroimaging studies are needed to establish the neural underpinnings of such enhanced cocaine-related choice.
患有可卡因使用障碍(CUD)的个体在选择时会优先选择可卡因而非非药物奖励。在两项新设计的带有图片的实验室任务中,我们记录了在可卡因给药范式之外的这种改变后的选择。
在20名患有CUD的受试者和20名匹配的健康对照受试者中,研究了他们在明确条件下(在两张并排完全可见的图像之间进行选择)以及更隐含条件下(在翻过来的卡片下隐藏的图片之间进行选择)观看可卡因、愉悦、不愉快或中性图片的选择情况。受试者还对每张图片的愉悦度和唤起感进行了自我报告评分。
在两种条件下,患有CUD的受试者选择观看的可卡因图片比对照受试者更多,这种组间差异并未完全由自我报告的图片评分所解释。此外,虽然患有CUD的受试者观看可卡因图片的选择超过了观看不愉快图片的选择(但与他们的自我报告评分相反,并未超过观看愉悦图片的选择),但健康对照受试者避免观看可卡因图片的频率与观看不愉快图片的频率相同,甚至更高。最后,观看可卡因图片选择最多的患有CUD的受试者,即使直接与观看愉悦图片的选择进行比较,也报告了最近最频繁的可卡因使用情况。
即使对于非药理学(图片)刺激,也能证明可卡因成瘾中与药物相关的选择增强。这种由替代刺激调节的选择部分超越了自我报告(可能表明可卡因成瘾中自我报告与客观行为之间存在脱节),从而提供了成瘾严重程度的客观指标。需要进行神经影像学研究来确定这种增强的与可卡因相关选择的神经基础。