Atlanta Veterans Affairs Medical Center, 1670 Clairmont Road, Decatur, GA 30033, USA.
Atlanta Veterans Affairs Medical Center, 1670 Clairmont Road, Decatur, GA 30033, USA; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 12 Executive Park Drive Northeast #200, Atlanta, GA 30329, USA.
Schizophr Res. 2018 Sep;199:46-52. doi: 10.1016/j.schres.2018.02.057. Epub 2018 Mar 8.
Anhedonia is a core negative symptom of schizophrenia. Schizophrenia patients report largely intact pleasure in consuming rewards, but have impairments in generating motivated behavior to pursue rewards, and show reduced fMRI activation of the reward pathway during presentation of rewarded stimuli. A computer based task measuring the development of a response bias in favor of rewarded stimuli permits assessment of reward-induced motivation. We hypothesized that subjects with schizophrenia would be impaired on this task.
58 schizophrenia subjects (SCZ) and 52 healthy controls (CON) were studied with a signal detection task to assess reward responsiveness. In multiple trials over three blocks subjects were asked to correctly identify two stimuli that were paired with unequal chance of monetary reward. The critical outcome variable was response bias, the development of a greater percent correct identification of the stimulus that was rewarded more often.
An ANOVA on response bias with Block as a repeated-measures factor and Diagnosis as a between-group factor indicated that SCZ subjects achieved a lower bias to rewarded stimuli than CON subjects (F(1,105)=8.82, p=0.004, η=0.078). Post hoc tests indicated that SCZ subjects had significantly impaired bias in Block 1 (p=0.002) and Block 2 (p=0.05), indicating that SCZ were slower to achieve normal levels of bias during the session.
SCZ subjects were slower to develop response bias to rewarded stimuli than CON subjects. This finding is consonant with the hypothesis that people with schizophrenia have a blunted capacity to modify behavior in response to reward.
快感缺失是精神分裂症的核心阴性症状。精神分裂症患者报告说，他们在享受奖励方面基本保持完整的愉悦感，但在产生追求奖励的动机行为方面存在障碍，并且在呈现奖励刺激时，奖励通路的 fMRI 激活减少。一项基于计算机的任务，用于衡量对奖励刺激产生反应偏向的能力，可以评估奖励引起的动机。我们假设精神分裂症患者在这项任务上会有障碍。
58 名精神分裂症患者（SCZ）和 52 名健康对照者（CON）进行了一项信号检测任务，以评估奖励反应能力。在三个块的多个试验中，要求受试者正确识别两个与不同概率的金钱奖励配对的刺激。关键的结果变量是反应偏向，即更频繁地奖励刺激的识别百分比的发展。
对反应偏向进行的 ANOVA 分析，其中块为重复测量因素，诊断为组间因素，表明 SCZ 患者对奖励刺激的偏向低于 CON 患者（F（1,105）=8.82，p=0.004，η=0.078）。事后检验表明，SCZ 患者在块 1（p=0.002）和块 2（p=0.05）中的偏向明显受损，这表明 SCZ 在整个会议期间较慢地达到正常的偏向水平。
SCZ 患者对奖励刺激的反应偏向发展速度比 CON 患者慢。这一发现与精神分裂症患者在奖励反应方面的行为修正能力减弱的假设一致。
