ImportanceClinical theory and behavioral studies suggest that people experiencing suicidal crisis are often unable to find constructive solutions or incorporate useful information into their decisions, resulting in premature convergence on suicide and neglect of better alternatives. However, prior studies of suicidal behavior have not formally examined how individuals resolve the tradeoffs between exploiting familiar options and exploring potentially superior alternatives.ObjectiveTo investigate exploration and exploitation in suicidal behavior from the formal perspective of reinforcement learning.Design, Setting, and ParticipantsTwo case-control behavioral studies of exploration-exploitation of a large 1-dimensional continuous space and a 21-day prospective ambulatory study of suicidal ideation were conducted between April 2016 and March 2022. Participants were recruited from inpatient psychiatric units, outpatient clinics, and the community in Pittsburgh, Pennsylvania, and underwent laboratory and ambulatory assessments. Adults diagnosed with borderline personality disorder (BPD) and midlife and late-life major depressive disorder (MDD) were included, with each sample including demographically equated groups with a history of high-lethality suicide attempts, low-lethality suicide attempts, individuals with BPD or MDD but no suicide attempts, and control individuals without psychiatric disorders. The MDD sample also included a subgroup with serious suicidal ideation.Main Outcomes and MeasuresBehavioral (model-free and model-derived) indices of exploration and exploitation, suicide attempt lethality (Beck Lethality Scale), and prospectively assessed suicidal ideation.ResultsThe BPD group included 171 adults (mean [SD] age, 30.55 [9.13] years; 135 [79%] female). The MDD group included 143 adults (mean [SD] age, 62.03 [6.82] years; 81 [57%] female). Across the BPD (χ23 = 50.68; P < .001) and MDD (χ24 = 36.34; P < .001) samples, individuals with high-lethality suicide attempts discovered fewer options than other groups as they were unable to shift away from unrewarded options. In contrast, those with low-lethality attempts were prone to excessive behavioral shifts after rewarded and unrewarded actions. No differences were seen in strategic early exploration or in exploitation. Among 84 participants with BPD in the ambulatory study, 56 reported suicidal ideation. Underexploration also predicted incident suicidal ideation (χ21 = 30.16; P < .001), validating the case-control results prospectively. The findings were robust to confounds, including medication exposure, affective state, and behavioral heterogeneity.Conclusions and RelevanceThe findings suggest that narrow exploration and inability to abandon inferior options are associated with serious suicidal behavior and chronic suicidal thoughts. By contrast, individuals in this study who engaged in low-lethality suicidal behavior displayed a low threshold for taking potentially disadvantageous actions.

中文翻译：

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边缘型人格障碍和抑郁症的探索-利用和自杀行为


重要性临床理论和行为研究表明，经历自杀危机的人往往无法找到建设性的解决方案或将有用的信息纳入他们的决策中，导致自杀过早趋同和忽视更好的选择。然而，先前对自杀行为的研究尚未正式检查个人如何解决利用熟悉的选择和探索可能更好的替代方案之间的权衡。目的从强化学习的形式角度探讨自杀行为中的探索和利用。设计、设置和参与者2016 年 4 月至 2022 年 3 月期间进行了两项对大型一维连续空间的探索-利用的病例对照行为研究和一项为期 21 天的自杀意念前瞻性门诊研究。参与者从宾夕法尼亚州匹兹堡的住院精神病科、门诊诊所和社区招募，并接受了实验室和门诊评估。包括被诊断患有边缘型人格障碍 （BPD） 和中年和晚年重度抑郁症 （MDD） 的成年人，每个样本包括人口统计学上等同的群体，有高致死率自杀未遂史、低致死率自杀未遂、患有 BPD 或 MDD 但没有自杀未遂的个体，以及没有精神障碍的对照个体。MDD 样本还包括一个有严重自杀意念的亚组。主要结局和措施探索和利用的行为（无模型和模型衍生）指数、自杀未遂致死率（贝克致死量表）和前瞻性评估的自杀意念。结果BPD 组包括 171 名成人 （平均 [SD] 年龄，30.55 [9.13] 岁;135 名 [79%] 女性）。 MDD 组包括 143 名成人 （平均 [SD] 年龄，62.03 [6.82] 岁;81 名 [57%] 女性）。跨 BPD （χ23 = 50.68;P < .001） 和 MDD （χ24 = 36.34;P < .001） 样本中，具有高致死率自杀未遂的个体发现的选择比其他群体少，因为他们无法摆脱无奖励的选择。相比之下，那些低致死率尝试的人在有奖励和无奖励行为后容易发生过度的行为转变。在战略性早期勘探或开发方面没有发现差异。在门诊研究的 84 名 BPD 参与者中，有 56 人报告有自杀意念。探索不足也预测了事件自杀意念 （χ21 = 30.16;P < .001），前瞻性地验证病例对照结果。这些发现对混杂因素是稳健的，包括药物暴露、情感状态和行为异质性。结论和相关性研究结果表明，狭隘的探索和无法放弃劣质选择与严重的自杀行为和慢性自杀念头有关。相比之下，本研究中从事低致死率自杀行为的个体表现出采取潜在不利行动的低阈值。