Mood and Anxiety Disorders Program, NIMH Intramural Research Program, Bethesda, MD, USA.
Am J Psychiatry. 2010 Jan;167(1):47-55. doi: 10.1176/appi.ajp.2009.09030410. Epub 2009 Nov 16.
Classical conditioning features prominently in many etiological accounts of panic disorder. According to such accounts, neutral conditioned stimuli present during panic attacks acquire panicogenic properties. Conditioned stimuli triggering panic symptoms are not limited to the original conditioned stimuli but are thought to generalize to stimuli resembling those co-occurring with panic, resulting in the proliferation of panic cues. The authors conducted a laboratory-based assessment of this potential correlate of panic disorder by testing the degree to which panic patients and healthy subjects manifest generalization of conditioned fear.
Nineteen patients with a DSM-IV-TR diagnosis of panic disorder and 19 healthy comparison subjects were recruited for the study. The fear-generalization paradigm consisted of 10 rings of graded size presented on a computer monitor; one extreme size was a conditioned danger cue, the other extreme a conditioned safety cue, and the eight rings of intermediary size created a continuum of similarity from one extreme to the other. Generalization was assessed by conditioned fear potentiating of the startle blink reflex as measured with electromyography (EMG).
Panic patients displayed stronger conditioned generalization than comparison subjects, as reflected by startle EMG. Conditioned fear in panic patients generalized to rings with up to three units of dissimilarity to the conditioned danger cue, whereas generalization in comparison subjects was restricted to rings with only one unit of dissimilarity.
The findings demonstrate a marked proclivity toward fear overgeneralization in panic disorder and provide a methodology for laboratory-based investigations of this central, yet understudied, conditioning correlate of panic. Given the putative molecular basis of fear conditioning, these results may have implications for novel treatments and prevention in panic disorder.
经典条件作用在许多惊恐障碍的病因学解释中占有重要地位。根据这些解释，在惊恐发作期间出现的中性条件刺激物获得了引发惊恐的特性。引发惊恐症状的条件刺激物不仅限于原始的条件刺激物，而且被认为会泛化到与惊恐同时出现的刺激物，从而导致惊恐线索的扩散。作者通过测试惊恐障碍患者和健康受试者表现出的条件性恐惧泛化的程度，对惊恐障碍的这种潜在相关因素进行了基于实验室的评估。
研究招募了 19 名符合 DSM-IV-TR 诊断标准的惊恐障碍患者和 19 名健康对照者。恐惧泛化范式由计算机显示器上呈现的 10 个大小逐渐变化的环组成；一个极端大小是条件性危险线索，另一个极端大小是条件性安全线索，而中间大小的八个环则形成了从一个极端到另一个极端的相似性连续体。通过肌电图（EMG）测量的惊吓眨眼反射的条件性恐惧增强来评估泛化。
惊恐障碍患者的条件性恐惧泛化比对照组更强，表现为惊吓 EMG。惊恐障碍患者的条件恐惧泛化到与条件性危险线索相差多达三个单位的环，而对照组的泛化仅限于相差一个单位的环。
这些发现表明惊恐障碍患者对恐惧过度泛化的明显倾向，并提供了一种基于实验室的研究这种被忽视的惊恐障碍的核心条件相关因素的方法。鉴于恐惧条件作用的假定分子基础，这些结果可能对惊恐障碍的新型治疗和预防具有重要意义。
