Approach and avoidance learning in patients with major depression and healthy controls: relation to anhedonia
Approach and avoidance learning in patients with major depression and healthy controls: relation to anhedonia
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DOI：
10.1017/s0033291709990468
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发表时间：
2010-03-01
影响因子：
6.9
通讯作者：
Robbins, T. W.
中科院分区：
文献类型：
--
作者：
Chase, H. W.;Frank, M. J.;Robbins, T. W.
背景理解抑郁症的行为后果的核心是这样一种理论，即与正强化相比，这种疾病伴随着对负强化的敏感性增加（负偏差），而其他理论家则强调抑郁症对强化的敏感性整体降低（钝化）。在这项研究中，我们使用了一个概率选择任务，旨在独立检查学习率，以预测积极和消极的强化。23例抑郁症患者和23名健康对照者参加了本研究。没有证据表明，一个负偏置的任务，无论是在收购的任务或概括的学习信息。抑郁症患者在任务上的反应比对照组慢，但在强化后表现出与对照组相似的反应时间（RTs）调节。在训练阶段观察到钝化的证据，这反映在该阶段的逐个试验调整减少。然而，这种效应与Snaith-Hamilton快乐量表（SHAPS）测量的快感缺乏的严重程度相关，与总体抑郁严重程度无关。我们认为，在一组抑郁症患者中观察到的负面偏见或钝化可能取决于神经心理学任务和患者的症状测试。我们的研究结果提供了如何进一步测试这些理论的见解。
Background. Central to understanding of the behavioural consequences of depression has been the theory that the disorder is accompanied by an increased sensitivity to negative compared with positive reinforcement (negative bias), whereas other theorists have emphasized a global reduction in sensitivity to reinforcement in depression (blunting).Method. In this study, we used a probabilistic selection task that was designed to examine independently rates of learning to predict both positive and negative reinforcement. Twenty-three depressed out-patients and 23 healthy controls from the local population participated in the study.Results. No evidence for a negative bias was observed on the task, either during acquisition of the task or during generalization of the learned information. Depressed patients responded slower on the task than controls but showed a similar modulation of reaction times (RTs) as controls following reinforcement. Evidence for blunting was observed on the training phase, as reflected in reduced trial-by-trial adjustment during this phase. However, this effect was related specifically to the severity of anhedonia, as measured by the Snaith-Hamilton Pleasure Scale (SHAPS), and was independent of overall depression severity.Conclusions. We argue that the observation of a negative bias or blunting in a group of depressed patients may be dependent on the neuropsychological task and the symptoms of the patients tested. Our results provide insight into how these theories might be further tested.