使用迴向抑制作業探討具強迫傾向個體對症狀相關刺激的注意力抑制缺陷

研究目的與背景：強迫症(Obsessive-Compulsive Disorder; OCD)屬於異質性高的心理疾患，過去有許多研究發現其症狀和注意力抑制缺陷有關。早期研究較多採用中性刺激為實驗材料，後期則有研究者將實驗中所用之刺激材料改為症狀相關的素材，也就是足以引起患者焦慮的刺激材料(如馬桶、糞便…等等)，並且採用聲音、文字或者圖片的方式來呈現。注意力抑制缺陷係指當個體注意到威脅刺激時，會很難抑制自己不再去注意該威脅刺激，亦即很難將注意力轉移出該刺激。IOR (Inhibition of return)是人類在注意力處理歷程中的一種現象，個體在視覺搜尋中會抑制自己不要去注意已經查看過的位置，以利搜尋作業的進行，若個體具有IOR缺陷，可能導致個體不斷重複注意或搜尋同樣的位置，而這就和OCD患者會重複做出同樣行為(例如重複檢查)的症狀很類似。基於此論點，本研究的主要目的是透過IOR作業，希望檢驗高強迫傾向個體在面對症狀相關刺激時，其注意力抑制的表現是否會較低強迫傾向個體差，其次，個體的症狀嚴重程度越高，其注意力抑制缺陷是否會越嚴重。研究方法：本研究招募大學生為參與者，首先邀請500名大學生填寫莫斯利強迫症狀量表中文版(Maudsley Obsessive-Compulsive Inventory, MOCI) 量表，經過篩選並邀請符合條件的參與者，最後共有高強迫傾向參與者30人，以及低強迫傾向參與者30人參與本研究。所有參與者均完成迴向抑制作業，刺激材料為症狀相關之威脅字詞(包含重複檢查及清潔相關字詞)以及中性字詞。研究結果：研究結果發現兩組實驗參與者在面對清潔相關字詞時，低強迫傾向組表現出明顯的IOR效果，而高強迫傾向組則沒有明顯的IOR效果，顯示高強迫傾向組面對清潔字詞時可能有IOR缺損；而在面對中性字詞以及重複檢查相關字詞時，則兩組都表現出正常的IOR功能。相關分析的結果則顯示MOCI分數無論與反應時間或是IOR效果指標都沒有顯著的相關性。結論：本研究結果顯示在面對清潔相關字詞時，高強迫傾向者相較於低強迫傾向者有明顯的IOR缺損。高、低強迫傾向者在面對中性字詞時，皆表現出明顯的IOR效果。然而，在面對重複檢查相關字詞時，高強迫傾向者卻沒有IOR缺損。除此之外，本研究並未發現症狀嚴重程度與IOR效果之間的相關。

關鍵字

強迫症；迴向抑制；注意力偏誤；注意力抑制

並列摘要

Abstract Background and purpose. Obsessive-Compulsive disorder (OCD) is a highly heterogeneous psychological disorder. Several studies have found that the severity of obsessive-compulsive symptoms are correlated with the impairments of attentional inhibition deficits (i.e., inhibition of return deficits, IOR deficits). In earlier studies of IOR in OCD, researchers commonly used neutral stimuli in their experiment. Nevertheless, more recent studies have used symptom-related stimuli (words, sounds or pictures)that can evoke anxiety in OCD patients or participants with highly obsessive-compulsive (high-OC) tendencies (e. g., toilet, poop). People with attentional inhibition deficit show difficulty in disengaging their attention from threatening stimuli. Inhibition of return is an attention phenomenon that enable individual to inhibit the allocation of attention to locations that have been examined during visual search. Deficits of IOR cause individuals to repeatedly search the location that has already been explored. This deficit are assumed to be associated with repetitive behaviors such as repetitive checking and cleaning in patients with OCD or individuals with high-OC tendencies. Accordingly, the present study aims to investigate whether individuals with high-OC tendencies will show IOR deficits for symptom-related stimuli compared with individuals with low-OC tendencies. Moreover, the present study also aims to examine whether higher levels of OCD symptoms are correlated with greater IOR deficits. Method. A sample of 500 undergraduate students was screened using the Maudsley Obsessive-Compulsive Inventory, MOCI). Thirty participants with high-OC tendencies and 30 participants with low-OC tendencies completed this study. Participants were asked to complete the IOR task with symptom-related (i.e., checking-related and cleaning-related words) and neutral words as stimulus materials. Result. The results showed that the low-OC group demonstrated a significant IOR effect for cleaning-related words, whereas the high-OC group did not. Both the high-OC and low-OC groups exhibited significant IOR effects for checking-related and neutral words. Moreover, the correlation analysis showed that no significant correlations between the MOCI scores and reaction time or between the MOCI scores and IOR effects. Discussion. Findings of the present study suggested that individuals with high-OC tendencies showed significant IOR deficits for cleaning-related stimuli compared with individuals with low-OC tendencies. Individuals with high-OC tendencies demonstrated IOR effects for neutral stimuli as well as individuals with low-OC tendencies did. However, individuals with high-OC tendencies did not show IOR deficits for checking-related stimuli. In addition, the levels of symptom severity were not significant correlated with the magnitude of IOR deficits.