What is Disgust and Its Clinical Importance? (Introduction)

• This paper argues that disgust is a primary emotional system—not just a reaction to bad taste but a complex mechanism that protects our internal environment.
• Understanding disgust can improve treatments for disorders such as obsessive-compulsive disorder (OCD), hypochondriasis, and fear of vomiting (emetophobia).
• It is placed within Panksepp’s Affective Neuroscience framework, showing that disgust has unique triggers and functions.

Background and Evolution of Disgust

• Initially overlooked as a “forgotten emotion,” research on disgust has grown significantly over the past two decades.
• Disgust goes beyond simple oral rejection (distaste) to include responses to unpleasant smells, sights, textures, and even moral violations.
• Think of disgust like a multi-sensor alarm system: it detects potential hazards before they cause harm.

Key Components and Functions of the Disgust System

• The DISGUST system, as defined by Toronchuk and Ellis, helps protect the body from pathogens by triggering avoidance and cleaning behaviors.
• It is activated by various sensory inputs—taste, smell, vision, touch—and by higher-level cognitive processes.
• Key terms are explained:
  • Distaste: A basic, short-lived rejection of bad-tasting food (like disliking a bitter medicine).
  • Nausea: The uneasy feeling that makes you want to vomit.
  • Retching: The physical action that often precedes vomiting.
  • Vomiting: The forceful expulsion of stomach contents as a last defense.
• In simple terms, the system works like a recipe: it detects a potential threat and then triggers a series of reactions to prevent harm.

Methodological Considerations in Studying Disgust

• Early studies used techniques like deep brain stimulation (DBS) in animals; however, many animals (such as rats) cannot vomit, making observation challenging.
• New methods—like genetic labeling and chemogenetic deactivation—allow researchers to observe retching-like behaviors even in non-emetic species.
• These advanced techniques help clarify the neural pathways and mechanisms that trigger disgust.

The Ancient Process of Defining the Internal Milieu

• The body must distinguish between “self” and “non-self” to protect against infections, a process known as autopoiesis.
• This is like building a self-sustaining fortress, where only friendly elements are allowed inside.
• Even in embryonic development, cells work together to establish boundaries—similar to how a community builds walls to defend a city.

Evolutionary Development of Disgust

• Disgust evolved as a defense mechanism to protect against harmful microbes and toxins.
• It likely began as a simple reflex (distaste) and developed into a more flexible system (DISGUST) capable of anticipatory responses.
• Imagine evolution as a chef perfecting a recipe over time, adding layers of complexity to better safeguard the body.

Neuroanatomical Substrates of Disgust

• Key brain regions include the anterior insular cortex (aIC), which is central to processing disgust.
• Other areas involved are the amygdala, basal ganglia, and brainstem regions like the nucleus tractus solitarius (NTS).
• These areas operate like parts of a security system—each monitors different aspects of a potential threat.
• There are species differences; for instance, the neural pathways in rodents differ from those in primates.

Disgust and the Immune System

• Disgust is closely linked to the immune system; it acts as an early warning when the body is at risk of infection.
• Experiments in mice show that activating certain brain regions (such as the insula) can trigger immune responses.
• The Compensatory Prophylaxis Hypothesis (CPH) suggests that when the immune system is suppressed, heightened disgust sensitivity compensates to protect the body.
• This is similar to a backup security system that becomes more vigilant when the main defenses are down.

Clinical Relevance: Why Disgust Matters in Psychiatry and Psychotherapy

• Dysregulation of the disgust system can lead to clinical problems such as:
  • OCD with contamination fears
  • Health anxiety (hypochondriasis)
  • Fear of vomiting (emetophobia)
• For example, patients with post-traumatic OCD may have heightened disgust responses that worsen their symptoms.
• Addressing disgust early in therapy is crucial—like fixing a faulty alarm system to prevent false alerts.

Additional Terminological Considerations

• Emotions can be understood in several layers:
  • Functional biological states (raw emotional reactions)
  • Conscious feelings (how we experience these emotions)
  • Emotional concepts (how we label and interpret these feelings)
• This paper emphasizes that the primary disgust system is distinct from simple distaste or nausea.
• Recognizing these differences can help clinicians tailor more effective treatments.

Implications for Psychotherapy

• Behavioral therapies like Exposure and Ritual Prevention (EX-RP) often target the visible expressions of disgust.
• Psychodynamic approaches focus on the patient’s narrative and the deeper, sometimes unrecognized, emotional concepts.
• Integrating a focus on disgust can improve outcomes by addressing both immediate reactions and deeper emotional memories.

Psychopathology and Treatment for OCD, Hypochondriasis, and Health Anxiety

• Research shows that:
  • High disgust sensitivity is linked to severe contamination fears in OCD.
  • Reductions in disgust propensity are correlated with improvements in OCD symptoms.
  • In children, high baseline disgust may predict poorer outcomes in behavioral therapy.
• These findings suggest that targeting the disgust system is key in treating these disorders.
• This is like recalibrating an overly sensitive sensor to reduce false alarms and improve overall function.

Summary and Future Directions

• The paper concludes that disgust is a complex, multi-layered emotional system vital for protecting our internal environment.
• It plays a significant role in various psychopathologies, making it an important target for therapeutic interventions.
• Future research should focus on:
  • Conducting more experimental studies using advanced techniques in animal models.
  • Clarifying the role of specific brain regions and neural pathways in processing disgust.
  • Developing clinical models that integrate disgust regulation with other emotional systems.
• A comprehensive understanding of disgust could lead to improved mental health treatments and a deeper insight into human emotions.

观察到了什么？ (引言)

• 本文主张，厌恶不仅仅是对不良味道的反应，而是一种原始情感系统，能够保护体内环境免受有害物质侵害。
• 理解厌恶有助于改善治疗，如强迫症（OCD）、疑病症以及呕吐恐惧症等疾病的疗效。
• 该观点基于潘克塞普的情感神经科学框架，显示出厌恶具有独特的触发机制和功能。

厌恶的背景与演化

• 曾被视为“被遗忘的情感”的厌恶，如今已成为研究重点，相关文献大幅增加。
• 厌恶不仅限于口腔排斥，还包括对难闻气味、怪异外观、奇异触感甚至道德违规行为的反应。
• 可以将厌恶看作一个多感官报警系统，在潜在威胁发生前提前发出警告。

厌恶系统的关键组成部分与功能

• Toronchuk和Ellis定义的DISGUST系统通过触发回避和清洁行为，保护体内免受病原体（细菌和毒素）的侵害。
• 该系统由多种感官输入（如味觉、嗅觉、视觉和触觉）以及高级认知过程激活。
• 关键术语解释：
  • 口腔排斥（Distaste）：对难吃食物的短暂、基本的拒绝（如对苦药的不喜）。
  • 恶心（Nausea）：一种让人感觉不适并想呕吐的体验。
  • 干呕（Retching）：常在呕吐前出现的反应。
  • 呕吐（Vomiting）：将胃内容物强制排出的防御性反应。
• 简单来说，这个系统就像一道食谱：先检测到潜在威胁，然后依次启动防御反应以防伤害。

研究厌恶的方法论考量

• 早期研究使用深脑刺激（DBS）等技术，但由于许多动物（如大鼠）不能呕吐，观察工作存在困难。
• 新方法如基因标记和化学遗传失活技术，使研究者能够在非呕吐物种中观察到类似干呕的行为。
• 这些先进技术帮助更好地揭示了触发厌恶的神经通路及其机制。

定义内部环境的古老过程

• 身体必须区分“自我”与“非自我”以防止感染，这一过程称为自我生成（autopoiesis）。
• 这类似于构建一个自给自足的堡垒，只允许友好成分进入。
• 即使在胚胎阶段，细胞也协同建立边界，就如同一个社区建造城墙以保卫家园。

厌恶的演化发展

• 厌恶作为防御机制进化而来，用于抵御有害微生物和毒素的侵袭。
• 它可能起初仅是一个简单的反射（口腔排斥），后逐渐发展成具有预防功能的复杂系统（DISGUST）。
• 可以将其比作一位厨师不断改进食谱，逐步增加复杂层次以更好地保护身体。

厌恶的神经解剖基础

• 关键脑区包括前岛叶皮层（aIC），在处理厌恶情绪中起着核心作用。
• 此外，杏仁核、基底神经节及脑干中的孤束核（NTS）等区域也非常重要。
• 这些区域各司其职，如同安全系统的不同部分，共同监控潜在威胁。
• 物种间存在差异，例如啮齿动物与灵长类动物的神经通路不同，影响厌恶的处理方式。

厌恶与免疫系统的关系

• 厌恶与免疫系统密切相关，当体内面临感染风险时，它会提前发出警报。
• 在小鼠实验中，激活特定脑区（如前岛叶）会引发免疫反应。
• 补偿性预防假说（CPH）认为，当免疫系统功能下降时，厌恶敏感性会提高以保护身体。
• 这类似于当主防御系统失效时，备用安全系统变得更加警觉。

临床相关性：为何厌恶对精神病学和心理治疗重要

• 厌恶系统的失调可能导致以下临床问题：
  • 以污染恐惧为特征的强迫症（OCD）
  • 健康焦虑（疑病症）
  • 呕吐恐惧症
• 例如，创伤后强迫症患者可能因过度厌恶反应而使症状加重。
• 在治疗中及早关注厌恶反应就像修复故障的报警系统，有助于防止误报并改善整体疗效。

额外的术语考量

• 情绪可分为几个层次：
  • 功能性生物状态（原始情感反应）
  • 主观感受（个人体验到的情绪）
  • 情感概念（我们如何标记和解释这些情绪）
• 本文强调，作为原始情感系统的厌恶，与简单的口腔排斥或恶心反应是不同的。
• 理解这些差异有助于临床医生制定更有效的治疗方案。

对心理治疗的启示

• 行为疗法，如暴露与反应预防（EX-RP），通常针对厌恶的外在表现进行干预。
• 心理动力学治疗则侧重于患者的叙述和深层情感概念，包括那些未被充分意识到的厌恶感。
• 将厌恶作为治疗目标，可以同时处理即时反应和深层情感记忆，从而提高治疗效果。

关于OCD、疑病症和健康焦虑的病理与治疗

• 研究显示：
  • 高厌恶敏感性与OCD中严重的污染恐惧密切相关。
  • 厌恶倾向的降低通常伴随着OCD症状的改善。
  • 在儿童中，基线厌恶水平较高可能预示着行为疗法效果较差。
• 这些发现表明，针对厌恶系统进行治疗是改善这些障碍的关键。
• 这就像重新校准过于敏感的传感器，从而减少误报并提升整体功能。

总结与未来方向

• 本文总结认为，厌恶是一种复杂且多层次的情感系统，对保护体内环境至关重要。
• 厌恶在多种精神病理中起着重要作用，因此成为治疗干预的一个关键目标。
• 未来研究应着重于：
  • 利用先进技术在动物模型中开展更多实验研究；
  • 阐明特定脑区和神经通路在厌恶处理中的作用；
  • 开发整合厌恶调控与其他情感系统的临床模型。
• 全面理解厌恶将有助于改进心理健康治疗，并加深我们对人类情感的认识。