BACKGROUND Addiction is supposedly characterized by a shift from goal-directed to habitual decision making, thus facilitating automatic drug intake. The two-step task allows distinguishing between these mechanisms by computationally modeling goal-directed and habitual behavior as model-based and model-free control. In addicted patients, decision making may also strongly depend upon drug-associated expectations. Therefore, we investigated model-based versus model-free decision making and its neural correlates as well as alcohol expectancies in alcohol-dependent patients and healthy controls and assessed treatment outcome in patients. METHODS Ninety detoxified, medication-free, alcohol-dependent patients and 96 age- and gender-matched control subjects underwent functional magnetic resonance imaging during the two-step task. Alcohol expectancies were measured with the Alcohol Expectancy Questionnaire. Over a follow-up period of 48 weeks, 37 patients remained abstinent and 53 patients relapsed as indicated by the Alcohol Timeline Followback method. RESULTS Patients who relapsed displayed reduced medial prefrontal cortex activation during model-based decision making. Furthermore, high alcohol expectancies were associated with low model-based control in relapsers, while the opposite was observed in abstainers and healthy control subjects. However, reduced model-based control per se was not associated with subsequent relapse. CONCLUSIONS These findings suggest that poor treatment outcome in alcohol dependence does not simply result from a shift from model-based to model-free control but is instead dependent on the interaction between high drug expectancies and low model-based decision making. Reduced model-based medial prefrontal cortex signatures in those who relapse point to a neural correlate of relapse risk. These observations suggest that therapeutic interventions should target subjective alcohol expectancies.

中文翻译：

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当习惯危险时：酒精预期和习惯性决策预测酒精依赖的复发

背景 据推测，成瘾的特征是从目标导向转变为习惯性决策，从而促进自动吸毒。两步任务允许通过将目标导向和习惯行为计算建模为基于模型和无模型控制来区分这些机制。在成瘾患者中，决策也可能在很大程度上取决于与药物相关的期望。因此，我们研究了基于模型与无模型的决策及其神经相关性以及酒精依赖患者和健康对照的酒精预期，并评估了患者的治疗结果。方法 90 名戒毒、无药物、酒精依赖患者和 96 名年龄和性别匹配的对照受试者在两步任务期间接受了功能性磁共振成像。酒精预期是用酒精预期问卷测量的。在 48 周的随访期间，37 名患者仍然戒酒，53 名患者复发，如酒精时间线随访方法所示。结果 复发患者在基于模型的决策过程中表现出内侧前额叶皮层激活减少。此外，高酒精预期与复发者基于模型的低控制相关，而在戒酒者和健康对照受试者中观察到相反的情况。然而，减少的基于模型的控制本身与随后的复发无关。结论 这些研究结果表明，酒精依赖的不良治疗结果不仅仅源于从基于模型到无模型控制的转变，而是取决于高药物预期和低基于模型的决策之间的相互作用。复发者基于模型的内侧前额叶皮层特征减少表明复发风险与神经相关。这些观察结果表明，治疗干预应针对主观酒精预期。