Bickel W K, Odum A L, Madden G J
Human Behavioral Pharmacology Laboratory, Department of Psychiatry, 38 Fletcher Place, University of Vermont, Burlington, VT 05401, USA.
Psychopharmacology (Berl). 1999 Oct;146(4):447-54. doi: 10.1007/pl00005490.
Impulsivity is implicated in drug dependence. Recent studies show problems with alcohol and opioid dependence are associated with rapid discounting of the value of delayed outcomes. Furthermore, discounting may be particularly steep for the drug of dependence.
We determined if these findings could be extended to the behavior of cigarette smokers. In particular, we compared the discounting of hypothetical monetary outcomes by current, never, and ex-smokers of cigarettes. We also examined discounting of delayed hypothetical cigarettes by current smokers.
Current cigarette smokers (n=23), never-smokers (n=22) and ex-smokers (n=21) indicated preference for immediate versus delayed money in a titration procedure that determined indifference points at various delays. The titration procedure was repeated with cigarettes for smokers. The degree to which the delayed outcomes were discounted was estimated with two non-linear decay models: an exponential model and a hyperbolic model.
Current smokers discounted the value of delayed money more than did the comparison groups. Never- and ex-smokers did not differ in their discounting of money. For current smokers, delayed cigarettes lost subjective value more rapidly than delayed money. The hyperbolic equation provided better fits to the data than did the exponential equation for 74 out of 89 comparisons.
Cigarette smoking, like other forms of drug dependence, is characterized by rapid loss of subjective value for delayed outcomes, particularly for the drug of dependence. Never- and ex-smokers could discount similarly because cigarette smoking is associated with a reversible increase in discounting or due to selection bias.
冲动性与药物依赖有关。最近的研究表明，酒精和阿片类药物依赖问题与对延迟结果价值的快速贴现有关。此外，对于成瘾药物，贴现可能特别陡峭。
我们确定这些发现是否可以扩展到吸烟者的行为。特别是，我们比较了当前吸烟者、从不吸烟者和曾经吸烟者对假设货币结果的贴现情况。我们还研究了当前吸烟者对延迟假设香烟的贴现情况。
当前吸烟者（n = 23）、从不吸烟者（n = 22）和曾经吸烟者（n = 21）在一个滴定程序中表明对即时与延迟货币的偏好，该程序确定了不同延迟下的无差异点。吸烟者对香烟重复该滴定程序。使用两个非线性衰减模型估计延迟结果的贴现程度：指数模型和双曲线模型。
当前吸烟者对延迟货币价值的贴现程度高于对照组。从不吸烟者和曾经吸烟者在货币贴现方面没有差异。对于当前吸烟者，延迟香烟比延迟货币更快地失去主观价值。在89次比较中的74次中，双曲线方程比指数方程更适合数据。
吸烟与其他形式的药物依赖一样，其特征是延迟结果的主观价值迅速丧失，尤其是对于成瘾药物。从不吸烟者和曾经吸烟者的贴现情况可能相似，因为吸烟与贴现的可逆增加或选择偏差有关。
