状态焦虑对条件性恐惧泛化的影响

恐惧的过度泛化是焦虑障碍患者重要的潜在病因,探索焦虑对恐惧泛化的影响具有重要意义。本研究在恐惧习得后,通过恐惧创伤电影范式诱发状态焦虑组被试的焦虑水平,采用主观预期值和皮电反应值作为指标,考察状态焦虑对条件性恐惧泛化的影响。结果表明,恐惧创伤电影范式显著提高了状态焦虑组被试的焦虑水平。在泛化阶段,状态焦虑组被试表现出更强的恐惧泛化,对与条件刺激相似的泛化刺激表现出更强烈的恐惧以及更高的预期。状态焦虑使得被试恐惧泛化的消退更慢,持续时间更长。研究同时发现,在状态焦虑下,被试对条件刺激的辨识出现增强趋势。研究结果提示在对经历负性事件个体进行临床干预时,可通过降低其焦虑水平来减少过度泛化。

The impact of state anxiety on fear generalization

Fear over-generalization has been put forward as a potential etiological factor of anxiety disorders. Previous studies have examined the phenomenon of fear generalization among individuals with anxiety disorders and high trait anxiety. However, state anxiety is more common in populations and its impact on fear generalization has not been paid attention to. Thus, in this study, we induced state anxiety in healthy individuals and tested the impact of state anxiety on fear generalization.
Thirty-eight healthy participants participated in the experiment and were randomly divided into an experimental group and a control group. The whole experiment consisted of four phases: habituation, acquisition, fear inducement, and generalization. In this experiment, 10 rings of gradually increasing size that were presented on a computer screen served as conditioned stimuli (CS) and generalization stimuli (GS). The rings in the two extreme sizes served as the conditioned danger cue (CS+) and conditioned safety cue (CS?), respectively. The eight intermediately sized rings served as four classes of generalization stimuli (i.e., GS1, GS2, GS3, and GS4), with GS4being the most similar one to CS+ in size. CS+ was probably paired with an unconditioned stimulus (US), while CS? and GS were unpaired with US. Six fear pictures from the international affective picture system (IAPS) were taken as US. During the experiment, subject online expectancy ratings and skin conductance responses (SCR) were recorded. During the habituation phase, the CS+ and CS? were each presented three times, each without any pictures following the CS+. During the acquisition phase, the CS+ and the CS? were presented six times each, and the pictures were presented 5s before each CS+ offset. During the fear inducement phase, the experimental group passively viewed a 5-min fear video and the control group passively viewed a 5-min video clip of a train traveling. The subsequent generalization phase consisted of six blocks. In each block, eight GSs were presented once without a picture; CS+ and CS? were presented twice each. One CS+ was followed by a picture to avoid the participants forgetting.
The results showed that exposure to the fear video significantly increased participants’ state anxiety. The experimental group displayed stronger generalization than control group. Conditioned fear in the experimental group was generalized to rings with up to GS4, GS3, and GS2in both SCR and online expectancy ratings,whereas generalization in control group was restricted to rings with only GS4in SCR or GS4andGS3in online expectancy ratings. The duration of generalization for the experimental group was longer than the control group in both SCR and online expectancy ratings, indicating that state anxiety slowed generalization extinction. Additionally, state anxiety enhanced the identification of conditioned stimuli in SCR.
The results of this study supported both the behavioral inhibition and behavioral activation theories. Regarding online expectancy ratings, the experimental group displayed stronger generalization than the control group, indicating the participants with state anxiety fail to inhibit fear responses in the presence of safety signals (i.e. GS). Regarding SCR, participants with state anxiety showed both the stronger behavioral inhibition to safety signals (i.e. GS) and behavioral activation to danger cues (CS+). Hence, the results indicated that the theories of behavioral inhibition and behavioral activation might occur in the different learning phases: the former one might occur in both explicit and implicit learning and the latter one might occur only in the implicit learning of fear. This study also has clinical implications. For individuals suffering from negative events, to decrease the state anxiety may be an effective method for reducing the fear over-generalization and improving the efficacy of exposure therapy.