Department of Psychiatry,University of Cambridge,Cambridge,UK.
Behavioural and Clinical Neuroscience Institute,University of Cambridge,Cambridge,UK.
Psychol Med. 2015 Mar;45(4):771-82. doi: 10.1017/S0033291714001834. Epub 2014 Aug 14.
Evidence suggests some overlap between the pathological use of food and drugs, yet how impulsivity compares across these different clinical disorders remains unclear. Substance use disorders are commonly characterized by elevated impulsivity, and impulsivity subtypes may show commonalities and differences in various conditions. We hypothesized that obese subjects with binge-eating disorder (BED) and abstinent alcohol-dependent cohorts would have relatively more impulsive profiles compared to obese subjects without BED. We also predicted decision impulsivity impairment in obesity with and without BED.
Thirty obese subjects with BED, 30 without BED and 30 abstinent alcohol-dependent subjects and age- and gender-matched controls were tested on delay discounting (preference for a smaller immediate reward over a larger delayed reward), reflection impulsivity (rapid decision making prior to evidence accumulation) and motor response inhibition (action cancellation of a prepotent response).
All three groups had greater delay discounting relative to healthy volunteers. Both obese subjects without BED and alcohol-dependent subjects had impaired motor response inhibition. Only obese subjects without BED had impaired integration of available information to optimize outcomes over later trials with a cost condition.
Delay discounting appears to be a common core impairment across disorders of food and drug intake. Unexpectedly, obese subjects without BED showed greater impulsivity than obese subjects with BED. We highlight the dissociability and heterogeneity of impulsivity subtypes and add to the understanding of neurocognitive profiles across disorders involving food and drugs. Our results have therapeutic implications suggesting that disorder-specific patterns of impulsivity could be targeted.
有证据表明，食物和药物的病理性使用之间存在一些重叠，但冲动性在这些不同的临床障碍中的比较仍不清楚。物质使用障碍通常以冲动性升高为特征，冲动性亚型在各种情况下可能具有共同性和差异性。我们假设与没有暴食障碍的肥胖患者相比，患有暴食障碍的肥胖患者和戒断酒精依赖的患者会有相对更多的冲动特征。我们还预测肥胖患者（无论是否患有暴食障碍）的决策冲动会受损。
30 名患有暴食障碍的肥胖患者、30 名没有暴食障碍的肥胖患者和 30 名戒断酒精依赖的患者以及年龄和性别匹配的对照组进行了延迟折扣（偏好较小的即时奖励而不是较大的延迟奖励）、反射冲动性（在证据积累之前快速决策）和运动反应抑制（对优势反应进行行动取消）测试。
所有三组与健康志愿者相比，延迟折扣都更大。没有暴食障碍的肥胖患者和酒精依赖患者的运动反应抑制都受损。只有没有暴食障碍的肥胖患者在有成本条件的情况下，在后续试验中无法整合可用信息以优化结果，表现出信息整合受损。
延迟折扣似乎是食物和药物摄入障碍的共同核心缺陷。出乎意料的是，没有暴食障碍的肥胖患者比患有暴食障碍的肥胖患者表现出更高的冲动性。我们强调了冲动性亚型的可分离性和异质性，并增加了对涉及食物和药物的各种障碍的神经认知特征的理解。我们的研究结果具有治疗意义，表明可以针对特定障碍的冲动性模式进行治疗。
