創傷後壓力疾患的風險途徑：創傷前-後認知脆弱性整合模型之前瞻性三波追蹤探討

Abstract

多數經歷創傷者不會發展出創傷後壓力疾患（PTSD），顯示創傷並非PTSD形成的充分條件，因此尋找PTSD的有效預測因子遂成為創傷領域的主要議題。PTSD預測因子可分為創傷前因子、創傷當時因子及創傷後因子。根據認知脆弱性-壓力模型的觀點，創傷當時與創傷後因子的影響性可能源自創傷前認知脆弱性的貢獻。回顧當前以基模論述PTSD的理論，可歸納出三類可能提升後續PTSD風險的創傷前認知脆弱因子，包括僵化正向基模、負向基模及矛盾基模。上述基模可能受創傷撼動或活化趨於負向，影響或加劇創傷當下與之後的負向認知與情緒反應，提高PTSD發生的風險。據此，本研究結合創傷前認知脆弱因子、創傷前因子、創傷時認知與情緒因子及創傷後認知因子，提出一創傷前-後認知脆弱性整合模型以說明PTSD的發展，並採用前瞻性三波設計進行探討。基線期（T0）參與者包含810位大學生，592人（73.1% ）在2個月後參與第一次追蹤（T1）。T0至T1期間有88人經歷新創傷，73人（83%）在3個月後繼續參與第二次追蹤（T2）。本研究扣除8位基線期符合PTSD者，以80位最近經歷新創傷者檢驗主要假設。分析指出，僵化正向信念者的後續PTSD症狀並未比非僵化者嚴重，反而較為輕微。先前負向信念可預測後續PTSD症狀，矛盾自我與慢性再經歷症狀有顯著相關。路徑分析指出認知脆弱性整合模型的適配理想，PTSD可能的風險途徑之一涉及創傷前長期憂鬱、先前負向信念、創傷當時的負向情緒與解離、創傷後負向信念與過度負向評估等因素的共同作用。另一可能的風險途徑只涉及創傷當時與創傷後因子的共同作用。上述結果顯示PTSD的發展可能涉及創傷前後的多重因素，此模型有助於整合以往創傷預測因子的知識。

Epidemiologic surveys indicate that a large proportion of general population has been exposed to traumatic events, but only a minority develops PTSD. Researchers have endeavored to identify risk factors that predict the emergence of PTSD. The risk factors of PTSD can be separated into pretrauma, peritraumatic, and posttrauma predictors. From the viewpoint of cognitive vulnerability-stress model, the effects of peritraumatic and posttrauma predictors may derive from prior cognitive vulnerability. Reviewing schema-based theories of PTSD suggests that three types of schematic representations may raise the risk of PTSD, including rigid/inflexible positive schema, negative schema, and contradictory schema. These schemata may be strongly shattered or activated by traumatic stressor, further leading to negative cognitive or emotional response during or after trauma, which contribute to PTSD symptoms. Based on the above, we proposed a pre- and post-trauma cognitive vulnerability integrated model to account for the development of PTSD, which comprises pretrauma cognitive vulnerability, pretrauma predictors, peritraumatic psychological responses, and posttrauma cognitive factors. The present study used a three-wave prospective design to investigate the statistical plausibility of the model. A total of 810 college students completed the baseline survey (T0), of whom 592 (73.1%) completed 2-month follow-up surveys (T1). Among those who completed T1 survey, 88 participants (14.9%) had experienced a new trauma during T0-T1 period, of whom 73 (83.0%) continued to join 3-month follow-up survey (T2). The final sample used to examine main hypotheses were 80 recently trauma-exposed individuals, after removing 8 probable PTSD cases at baseline. Results indicated that those who held rigid positive belief did not show higher PTSD severity than those who did not. In addition, prior negative belief predicted subsequent PTSD severity. Contradictory self predicted 3- to 4-month reexperiencing severity. Path analysis indicated that the proposed integrated model did fit the data well. One of the risk pathways for PTSD may involve the co-effects of pretrauma depression, prior negative belief, peritraumatic negative emotion and dissociation, posttrauma negative cognition, and maladaptive appraisals. Another risk pathway may involve the interaction of peritraumatic and posttrauma predictors. Findings have both theoretical and clinical implications.