Data from: Dissociable temporal effects of bupropion on behavioural measures of emotional and reward processing in depression

Background: Antidepressants remediate negative biases in emotional
processing early in treatment, prior to mood improvement. However, the
effects on reward processing potentially relevant to the treatment of
anhedonia are less clear. Here we investigate the early and sustained
effects of the dopamine and noradrenaline reuptake inhibitor bupropion on
behavioural measures of emotional and reward processing in currently
depressed individuals. Methods: 46 currently depressed patients and 42
healthy controls participated in a repeated measures study, during which
open-label bupropion was administered to only the patient group over a 6
week period without a placebo group. All participants completed the
Emotional Test Battery and a probabilistic instrumental learning task at
week 0, week 2 and week 6. Results: Currently depressed patients displayed
negative biases in emotional processing and blunted response bias for
high-probability wins compared to the healthy controls at baseline.
Bupropion was found to reduce the negative biases in emotional processing
early in treatment, including a significant decrease in the percentage
misclassification of other face emotions as sad and the number of negative
self-referent words falsely recalled between baseline and week 2.
Conversely, bupropion was found to initially further reduce the response
bias for high-probability wins between baseline and week 2. This effect
reversed with 6 weeks bupropion treatment and reward processing was
normalised compared to the healthy controls. Conclusions: Early in
treatment, bupropion acts to reduce negative biases in emotional
processing but exacerbates impaired reward processing. The beneficial
actions of bupropion on reward processing then occur later in treatment.
Such dissociation in the temporal effects of bupropion on emotional and
reward processing has implications for the treatment of the different
symptom domains of negative affect and anhedonia in depression.

研究背景：抗抑郁药可在治疗早期、情绪症状改善之前，纠正情绪加工中的负性偏差。然而，其对与快感缺失（anhedonia）治疗相关的奖赏加工的影响尚不明确。本研究旨在探讨多巴胺（dopamine）和去甲肾上腺素（noradrenaline）再摄取抑制剂安非他酮（bupropion）对当前确诊抑郁症患者的情绪与奖赏加工行为学指标的早期及持续效应。

研究方法：本研究为重复测量设计，共纳入46名当前确诊抑郁症患者与42名健康对照。仅患者组接受开放标签安非他酮治疗，疗程6周，未设置安慰剂对照组。所有受试者分别于第0周、第2周及第6周完成情绪测试电池（Emotional Test Battery）与概率性工具性学习任务。

研究结果：基线状态下，与健康对照相比，抑郁症患者表现出情绪加工的负性偏差，且对高概率获胜的反应偏差显著钝化。安非他酮可在治疗早期降低情绪加工的负性偏差，包括将其他面部情绪错误归类为悲伤情绪的比例显著下降，且基线至第2周间错误回忆的负性自我相关词汇数量显著减少。与之相反，安非他酮在基线至第2周间最初进一步降低了高概率获胜的反应偏差。该效应在6周治疗后发生逆转，奖赏加工功能恢复至与健康对照相当的正常水平。

研究结论：治疗早期，安非他酮可降低情绪加工的负性偏差，但会加重奖赏加工的受损程度。随后，安非他酮对奖赏加工的有益作用才会在治疗后期显现。安非他酮对情绪与奖赏加工的时序效应存在解离，这为抑郁症中负性情绪与快感缺失这两类不同症状领域的治疗提供了理论启示。