Shiffman S, Fischer L B, Zettler-Segal M, Benowitz N L
Department of Psychology, University of Pittsburgh, Pa.
Arch Gen Psychiatry. 1990 Apr;47(4):333-6. doi: 10.1001/archpsyc.1990.01810160033006.
Most theories of dependence imply that repeated exposure to an addictive drug leads inexorably to dependence. We examined nicotine exposure in "tobacco chippers," who smoke regularly without developing dependence. Blood samples were obtained before and after 10 chippers (smoking up to 5 cigarettes per day) and 12 dependent smokers (20 to 40 cigarettes per day) smoked a cigarette. Chippers' blood nicotine levels increased significantly, in amounts equaling those of dependent smokers. Assays of cotinine (a long-lasting nicotine metabolite) also suggested that chippers' per-cigarette nicotine absorption equaled that of dependent smokers. Chippers' cotinine levels were also compared with those of heavy smokers (38 cigarettes per day) whose consumption was reduced to 5 cigarettes per day in a previously published study. The heavy smokers compensated by tripling their per-cigarette nicotine intake. Chippers did not seem to be compensating; their cotinine values equaled those expected when regular smokers were not compensating for reduced cigarette availability.
大多数成瘾理论认为，反复接触成瘾性药物必然会导致成瘾。我们研究了“轻度吸烟者”的尼古丁接触情况，他们有规律地吸烟但未成瘾。在10名轻度吸烟者（每天吸烟不超过5支）和12名成瘾吸烟者（每天吸20至40支烟）吸完一支烟前后采集血样。轻度吸烟者的血液尼古丁水平显著升高，升高幅度与成瘾吸烟者相当。可替宁（一种长效尼古丁代谢物）检测也表明，轻度吸烟者每支烟的尼古丁吸收率与成瘾吸烟者相当。还将轻度吸烟者的可替宁水平与重度吸烟者（每天吸38支烟）的可替宁水平进行了比较，在之前发表的一项研究中，这些重度吸烟者的吸烟量减少至每天5支。重度吸烟者通过将每支烟的尼古丁摄入量增加两倍来进行补偿。轻度吸烟者似乎没有进行补偿；他们的可替宁值与正常吸烟者未因香烟供应量减少而进行补偿时预期的值相当。
