Grillon Christian, Pine Daniel S, Lissek Shmuel, Rabin Stephanie, Bonne Omer, Vythilingam Meena
Mood and Anxiety Disorders Program, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-2670, USA.
Biol Psychiatry. 2009 Jul 1;66(1):47-53. doi: 10.1016/j.biopsych.2008.12.028. Epub 2009 Feb 12.
Uncontrollability and unpredictability are key concepts related to re-experiencing, avoidance, and hypervigilance symptoms of posttraumatic stress disorder (PTSD). However, little is known about the differential sensitivity of PTSD individuals to unpredictable stressors, relative to either healthy individuals or individuals with other anxiety disorders. This study tested the hypothesis that elevated anxious reactivity, specifically for unpredictable aversive events, is a psychophysiological correlate of PTSD.
Sixteen patients with PTSD (34.5 +/- 12.4 years) were compared with 18 patients with generalized anxiety disorder (GAD) (34.0 +/- 10.5 years) and 34 healthy control subjects (30.2 +/- 8.5 years). Participants were exposed to three conditions: one in which predictable aversive stimuli were signaled by a cue, a second in which aversive stimuli were administered unpredictably, and a third in which no aversive stimuli were anticipated. Startle magnitude was used to assess anxious responses to the threat cue and to contexts associated with each condition.
Posttraumatic stress disorder and GAD patients showed normative enhancement of fear to the predictable threat cue, but the PTSD group displayed elevated anxiety during the unpredictable condition compared with participants with GAD and healthy control subjects.
Anxious reactivity to unpredictable aversive events was heightened in PTSD but not in GAD and healthy subjects. Prior works also found signs of increased reactivity to unpredictable threat in panic disorder (PD), suggesting that PTSD and PD may involve shared vulnerability. As such, the current results inform understandings of classification, pathophysiology, and psychopharmacology of anxiety disorders, generally, and PTSD and panic disorder specifically.
不可控性和不可预测性是与创伤后应激障碍（PTSD）的重新体验、回避和过度警觉症状相关的关键概念。然而，相对于健康个体或患有其他焦虑症的个体，PTSD个体对不可预测应激源的差异敏感性知之甚少。本研究检验了以下假设：焦虑反应增强，特别是对不可预测的厌恶事件的反应增强，是PTSD的心理生理相关因素。
将16名PTSD患者（34.5±12.4岁）与18名广泛性焦虑障碍（GAD）患者（34.0±10.5岁）和34名健康对照者（30.2±8.5岁）进行比较。参与者暴露于三种条件下：一种是通过提示信号发出可预测的厌恶刺激，第二种是不可预测地给予厌恶刺激，第三种是不预期有厌恶刺激。惊吓幅度用于评估对威胁提示以及与每种条件相关的情境的焦虑反应。
PTSD和GAD患者对可预测的威胁提示表现出正常的恐惧增强，但与GAD患者和健康对照者相比，PTSD组在不可预测条件下表现出更高的焦虑水平。
PTSD患者对不可预测的厌恶事件的焦虑反应增强，而GAD患者和健康受试者则没有。先前的研究还发现惊恐障碍（PD）患者对不可预测威胁的反应性增加的迹象，表明PTSD和PD可能存在共同的易感性。因此，目前的结果有助于理解焦虑症的分类、病理生理学和心理药理学，特别是PTSD和惊恐障碍。
