以負向促發作業探討強迫症患者與其他焦慮症患者對於情緒面孔之注意抑制及記憶提取

Attention Inhibition and Memory Retrieval toward Emotional Faces on Patients of Obsessive Compulsive Disorder and Other Anxiety Disorders: Using Negative Priming Paradigm

研究目的：本研究主要驗證強迫症與其他焦慮症患者的「抑制缺損」以及「認知逃避」假設，並探討個體對於陌生面孔刺激的「注意抑制」與「記憶提取」歷程。研究方法：作業使用夾擊典範負向促發作業，受試者包括未使用藥物治療的強迫症與其他焦慮症之初診病患，及配對的正常人。所有病人的焦慮程度以「焦慮狀態—特質量表」控制在同一水平。研究結果：ANOVA反應時間分析結果顯示，正常人出現中性與威脅負向促發效應，其他焦慮症患者未出現中性負向促發效應，卻出現威脅負向促發效應，而強迫症患者的負向促發效應則均消失。研究結論：研究結果驗證抑制缺損假設及暗示可能的認知逃避效果，且強迫症患者與其他焦慮症患者具有明顯不同的表現型態，暗示兩者具不同的病理機制。討論中並納入可能的注意抑制及記憶提取作用，並說明患者在臨床症狀上的相關表現。

Purpose: Evidence from Stroop and the probe detection task has shown that anxious individuals reveal an attentional bias to threat, suggesting that anxiety may cause a deficiency in filtering out threatening stimuli. Recently, researchers using negative proming tasks have found the defect inhibition and cognitive avoidance processes in anxious individuals. However, research based on these two processes has produced inconsistent results; therefore we conducted this study. Negative priming effects, the increase in response time to targets previously encountered as distracters, were explained by attributing them to the attentional inhibitory mechanism that blocks access to distracter representations at prime display; they were also explained by the memory retrieval mechanism that retrieves the conflict tags at probe display. In this study we tried to confirm the defect inhibition hypothesis and assumed a vanished negative priming effect in anxious individuals. We also tried to see if there was a different threat-related negative priming that may differentiate between the inhibition and the retrieval process in these anxious individuals. Methods: Subjects included twenty two medication-free patients of obsessive-compulsive disorder (OCD) and twenty one medication-free patients of other anxiety disorders (OAD), as well as thirty matched healthy subjects without any psychiatric history. Each subject’s anxiety level was evaluated by the use of the State-Trait Anxiety Inventory. The Flanker paradigm of the negative priming task was used. Subjects viewed prime-probe pairs of unfamiliar neutral and threatening faces and were required to decide whether target faces were the same or different while ignoring the distracting faces. The stimulus locations were fixed and the experimental variables were repetition (repeating and non-repeating) and stimulus valence (neutral and threatening). Subjects’ button-push reaction times were recorded and analyzed by the use of the ANOVA statistical method. Results: In prime conditions, a significant interaction effect was found between prime conditions and groups as the result of a three by two ANOVA. Further comparison revealed that the OCD group had a significantly longer response time to the threatening distracting condition compared to the neutral distracting condition. In probe conditions, a significant interaction between probe conditions and groups was found. Healthy subjects showed significant negative priming effects toward both neutral and threatening stimuli. All patients’ negative priming effects disappeared, except that OAD patients revealed a significant negative priming effect in threatening condition. Results remained the same after we controlled the variation in each subject’s baseline reaction time by the use of the ANCOVA statistical method. The results of the scores of anxiety levels showed that both OCD and OAD groups had significantly higher levels of anxiety compared to the normal group. Conclusions: The defect inhibition hypothesis under anxiety was confirmed in this study. The results indicated that OCD patients might have a prevalent inhibition deficit toward distracting stimuli. On the other hand, OAD patients’ responsive pattern might be explained by cognitive avoidance or an increased memory retrieval effect toward threatening distracting stimuli. We further hypothesized that anxiety may alter representations of distracters and result in a stronger threat-related retrieval process as well as a defect inhibition process. However, this hypothesis needs to be supported by future research. Relative neuropsychological pathology might be related to the dysfunctional amygdala, which processes the threat related stimuli and the facial stimuli as well. Some clinical meanings and applications were also discussed. More follow up research is necessary to differentiate the possible different roles played by the attention inhibition and the memory retrieval mechanisms in patients with anxiety disorders.