Negative expectancies in posttraumatic stress disorder: Neurophysiological (N400) and behavioral evidence

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• 作者：Matthew Kimble^a ; ^{mkimble@middlebury.edu} ; Laura Batterink^b ; Elizabeth Marks^c ; Cordelia Ross^a ; Kevin Fleming^d
• 关键词：PTSD ; Negative appraisals ; Expectancy bias ; Attention ; Hypervigilance ; Threat ; N400 ; Event-related potentials
• 刊名：Journal of Psychiatric Research
• 出版年：2012
• 期刊代码：169_00223956
• 类别：med
• 出版时间：July, 2012
• 卷：46
• 期：7
• 页码：849-855
• 文件大小：466 K

摘要

Background

Posttraumatic stress disorder (PTSD) is a disorder that theoretically and clinically is thought to be associated with persistent and exaggerated negative expectancies. This study used the N400 event-related potential (ERP) to investigate expectancies for threatening endings to ambiguous sentence stems. The N400 ERP is thought to reflect the amount of effort required to integrate a stimulus into a given context. In sentence reading tasks, the N400 is reliably larger when a word is unexpected.

Method

In this study, fifty-seven trauma survivors of various types (22 with PTSD and 35 without) read ambiguous sentence stems on a computer screen. These sentence stems were completed with either an expected (鈥淭he unfortunate man lost his鈥?span class="underline">wallet鈥?, unexpected (鈥淭he unfortunate man lost his鈥?span class="underline">artist鈥?, or threatening word endings (鈥淭he unfortunate man lost his鈥?span class="underline">leg鈥?.

Results

Participants with PTSD, as compared to those without, showed significantly smaller N400s to threatening sentence endings suggesting enhanced expectancies for threat. Behavioral responses supported this conclusion.

Conclusions

These findings are consistent with the clinical presentation of hypervigilance and proposed revisions to the DSM-V that emphasize persistent and exaggerated negative expectations about one's self, others, or the world. Relative to earlier behavioral studies, this work further suggests that this expectancy bias occurs automatically and at the early stages of information processing. The discussion focuses on the potential impact of a negative expectancy bias in PTSD and the value of the ambiguous sentence paradigm for studying PTSD as well as other disorders.