Physical dependence increases the relative reinforcing effects of caffeine versus placebo
Physical dependence increases the relative reinforcing effects of caffeine versus placebo
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DOI：
10.1007/s002130050704
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发表时间：
1998-10-01
影响因子：
3.4
通讯作者：
Griffiths, RR
中科院分区：
文献类型：
--
作者：
Garrett, BE;Griffiths, RR
这项研究采用受试者内部交叉设计，通过实验操作身体依赖来检验身体依赖在咖啡因强化中的作用。每个受试者被暴露于两个慢性药物阶段(300 mg/70 kg/d咖啡因和安慰剂)9-12天，不同受试者之间的阶段顺序平衡。在每个慢性药物暴露后的两天，受试者按平衡顺序接受急性剂量的咖啡因(300毫克/70公斤)或安慰剂。然后，通过多项选择程序来确定这些药物的强化效果。在多项选择程序中，受试者在接受不同数额的钱或再次接受药物之间做出一系列不同的选择，以及在两种药物之间做出选择。为了确保受试者仔细填写表格，在接触了两种急性给药后，受试者从多项选择表中随机选择了一项，并实施了该选择的结果。当受试者长期服用咖啡因时，与其他三种情况相比，他们愿意放弃更多的钱，并且在接受安慰剂后典型的戒断症状(如疲劳、情绪障碍)显著增加。当受试者长期服用咖啡因时，他们也选择接受咖啡因而不是安慰剂，其频率是长期服用安慰剂时的两倍。这些发现提供了迄今为止最有力的证据，表明咖啡因的身体依赖增加了咖啡因与安慰剂相比的相对强化效果。
Using a within-subject cross-over design, this study examined the role of physical dependence in caffeine reinforcement by experimentally manipulating physical dependence. Each subject was exposed to two chronic drug phases (300 mg/70 kg/day caffeine and placebo) for 9-12 days, with order of phases counterbalanced across subjects. On 2 separate days immediately following each of the chronic drug exposures, subjects received acute doses of either caffeine (300 mg/70 kg) or placebo in counterbalanced order. The reinforcing effects of these drugs were then determined by using a multiple-choice procedure in which subjects made a series of discrete choices between receiving varying amounts of money or receiving the drug again, and a choice between the two drugs. To ensure that subjects completed the form carefully, following exposure to both of the acute drug administrations, one of the subject's previous choices from the multiple-choice form was randomly selected and the consequence of that choice was implemented. When subjects were maintained on chronic caffeine, they were willing to forfeit significantly more money and showed significant increases in typical withdrawal symptoms (e.g. fatigue, mood disturbance) after receiving placebo as compared to the other three conditions. When subjects were maintained on chronic caffeine, they also chose to receive caffeine over placebo twice as often than when they were maintained on chronic placebo. These findings provide the strongest evidence to date indicating that caffeine physical dependence increases the relative reinforcing effects of caffeine versus placebo.