Background and objectives

Dysfunction in reward processing is a hallmark feature of depression. In the context of reinforcement learning, previous research has linked depression with reliance on simple habit-driven (‘model-free’) learning strategies over more complex, goal-directed (‘model-based’) strategies. However, the relationship between depression and habit-breaking remains an under-explored research area. The current study sought to bridge this gap by investigating the effect of depressive symptoms on habit formation and habit-breaking under monetary and social feedback conditions. Additionally, we examined whether spontaneous eyeblink rate (EBR), an indirect marker for striatal dopamine levels, would modulate such effects.

Methods

Depressive symptoms were operationalized using self-report measures. To examine differences in habit formation and habit breaking, undergraduate participants (N = 156) completed a two-stage reinforcement learning task with a devaluation procedure using either monetary or social feedback.

Results

Regression results showed that in the monetary feedback condition, spontaneous EBR moderated the relationship between depressive symptoms and model-free strategies; individuals with more depressive symptomatology and high EBR (higher dopamine levels) exhibited increased reliance on model-free strategies. Depressive symptoms negatively predicted devaluation sensitivity, indicative of difficulty in habit-breaking, in both monetary and social feedback contexts.

Limitations

Social feedback relied on fixed feedback rather than real-time peer evaluations; depressive symptoms were measured using self-report rather than diagnostic criteria for Major Depressive Disorder; dopaminergic functioning was measured using EBR rather than PET imaging; potential confounds were not controlled for.

Conclusions

These findings have implications for identifying altered patterns of habit formation and deficits in habit-breaking among those experiencing depressive symptoms.

中文翻译：

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检查抑郁症状对习惯形成和打破习惯的影响

背景和目标

奖励处理功能障碍是抑郁症的标志性特征。在强化学习的背景下，先前的研究将抑郁症与依赖简单的习惯驱动（“无模型”）学习策略联系起来，而不是更复杂的目标导向（“基于模型”）策略。然而，抑郁症与打破习惯之间的关系仍然是一个未充分探索的研究领域。目前的研究试图通过调查在金钱和社会反馈条件下抑郁症状对习惯形成和打破习惯的影响来弥合这一差距。此外，我们检查了自发眨眼率 (EBR)（纹状体多巴胺水平的间接标志物）是否会调节这种效果。

方法

使用自我报告措施对抑郁症状进行操作。为了检查习惯形成和习惯打破的差异，本科参与者 (N = 156) 完成了一个两阶段强化学习任务，并使用货币或社会反馈进行贬值程序。

结果

回归结果表明，在货币反馈条件下，自发的EBR调节了抑郁症状与无模型策略之间的关系；具有更多抑郁症状和高 EBR（更高的多巴胺水平）的个体表现出对无模型策略的依赖程度更高。抑郁症状负面预测贬值敏感性，表明在货币和社会反馈背景下难以改掉习惯。

限制

社会反馈依赖于固定的反馈而不是实时的同行评价；抑郁症状是使用自我报告而不是重度抑郁症的诊断标准来衡量的；使用 EBR 而不是 PET 成像测量多巴胺能功能；潜在的混淆没有得到控制。

结论

这些发现对于识别出现抑郁症状的人的习惯形成模式的改变和打破习惯的缺陷具有重要意义。