Department of Psychiatry and Neuroimaging Center, Technische Universität Dresden, 01187, Dresden, Germany.
Department of Psychiatry and Psychotherapy, University of Tübingen, 72076, Tübingen, Germany.
Psychopharmacology (Berl). 2021 Feb;238(2):399-410. doi: 10.1007/s00213-020-05688-5. Epub 2020 Nov 20.
Smokers discount delayed rewards steeper than non-smokers or ex-smokers, possibly due to neuropharmacological effects of tobacco on brain circuitry, or lower abstinence rates in smokers with steep discounting. To delineate both theories from each other, we tested if temporal discounting, choice inconsistency, and related brain activity in treatment-seeking smokers (1) are higher compared to non-smokers, (2) decrease after smoking cessation, and (3) predict relapse.
At T1, 44 dependent smokers, 29 non-smokers, and 30 occasional smokers underwent fMRI while performing an intertemporal choice task. Smokers were measured before and 21 days after cessation if abstinent from nicotine. In total, 27 smokers, 28 non-smokers, and 29 occasional smokers were scanned again at T2. Discounting rate k and inconsistency var(k) were estimated with Bayesian analysis.
First, k and var(k) in smokers in treatment were not higher than in non-smokers or occasional smokers. Second, neither k nor var(k) changed after smoking cessation. Third, k did not predict relapse, but high var(k) was associated with relapse during treatment and over 6 months. Brain activity in valuation and decision networks did not significantly differ between groups and conditions.
Our data from treatment-seeking smokers do not support the pharmacological hypothesis of pronounced reversible changes in discounting behavior and brain activity, possibly due to limited power. Behavioral data rather suggest that differences between current and ex-smokers might be due to selection. The association of choice consistency and treatment outcome possibly links consistent intertemporal decisions to remaining abstinent.
吸烟者对延迟奖励的折扣幅度大于非吸烟者或戒烟者，这可能是由于烟草对大脑回路的神经药理学作用，或者是由于折扣幅度较大的吸烟者戒烟率较低。为了将这两种理论区分开来，我们测试了治疗中的吸烟者（1）是否比非吸烟者的时间折扣、选择不一致和相关的大脑活动更高，（2）在戒烟后是否减少，以及（3）是否可以预测复发。
在 T1 时，44 名依赖吸烟者、29 名非吸烟者和 30 名偶尔吸烟者在进行跨期选择任务时接受 fMRI 扫描。如果吸烟者在戒烟后 21 天内没有尼古丁摄入，将在 T1 和 T2 进行测量。使用贝叶斯分析估计折扣率 k 和不一致性 var(k)。
首先，治疗中的吸烟者的 k 和 var(k)并不高于非吸烟者或偶尔吸烟者。其次，戒烟后 k 和 var(k)均未改变。第三，k 不能预测复发，但高 var(k)与治疗期间和 6 个月以上的复发有关。在评估和决策网络中的大脑活动在组间和条件间没有显著差异。
我们来自治疗中的吸烟者的数据不支持折扣行为和大脑活动明显可逆变化的药理学假说，这可能是由于功率有限。行为数据表明，当前吸烟者和戒烟者之间的差异可能是由于选择造成的。选择一致性和治疗结果的关联可能将一致的跨期决策与保持禁欲联系起来。
