抑郁症人群的心境一致性认知偏向*

何振宏 张丹丹 罗跃嘉

(深圳大学情绪与社会认知科学研究所,深圳 518060)

抑郁症是一种常见的复发性心境障碍(mood disorder),在临床上又称重度抑郁障碍(major depressive disorder,MDD)。在抑郁症的诸多致病因素中,认知因素特别是认知偏向(对负性信息的过度关注)是抑郁症状产生、持续和发展的重要原因之一(Taylor & John,2004)。这种由于抑郁等心境障碍引起的对负性信息的过度关注被称为心境一致性偏向(mood-congruent bias) (Delle-Vigne,Wang,Kornreich,Verbanck,& Campanella,2014)。Beck曾在其抑郁认知模型中提出,认知加工对心境一致性信息的偏好维持了抑郁的心境状态(Beck,1967)。新近的抑郁认知理论认为抑郁症状是由心境一致性情绪加工偏向(Mood-congruent emotion processing bias)所引起(Beck,2008; Scher,Ingram,& Segal,2005)。这两种理论提到的认知加工偏向和情绪加工偏向其实是从认知或情绪角度对抑郁症人群心境一致性偏向的表述,为简化表述,统称其为认知偏向。Joormann等人认为,认知偏向可能会增加抑郁发作的易感性(vulnerability)(Joormann,Gilbert,& Gotlib,2010)。MDD病人由于注意和记忆的严重损害,其认知偏向可能会妨碍言语信息传递的有效性(Everaert,Koster,&Derakshan,2012),甚至抵消治疗干预的效果(Baert,Koster,& de Raedt,2011)。因此无论从理论还是临床角度看来,对抑郁症认知偏向进行一个整体和深入的了解十分必要。

目前国外已有一些探讨抑郁症认知偏向的综述文献,但有的综述并没有将该认知偏向当作核心论述主题,如Mathews等人的综述(Mathews &MacLeod,2005); 另一些综述则引证单一,且多集中于脑成像学的证据(Roiser,Elliott,&Sahakian,2012)。类似地,国内也有一篇依据Beck抑郁认知模型对该认知偏向脑成像研究的综述(杨娟,张小崔,姚树桥,2014)。然而,该认知偏向还有来自其他领域(行为学和电生理学)不容忽视的研究证据,且目前国外对该认知偏向的一些新的研究动态值得我们关注,比如工作记忆偏向,而这是先前理论模型所不曾包含的。因此,在介绍该认知偏向时我们更多从实证角度出发,结合行为、电生理以及脑成像等多方面证据总结抑郁病人在认知加工过程中的偏向特点,在验证相关的理论模型的同时,为临床诊断提供抑郁症认知过程异常的有关生物指标(biomarker)。我们从三个基本的认知加工领域(知觉、注意和记忆)以及较高级的认知领域(认知解释),对抑郁症的认知偏向相关研究进行系统回顾,并进一步总结了该认知偏向的三个特点和相应的脑机制,提出该领域研究有待回答的问题和对未来研究的展望。

1 心境一致性知觉偏向

抑郁症人群的知觉偏向表现为对负性刺激尤其是悲伤刺激有更好和更准确的知觉加工,而对正性刺激则呈现相反模式。研究情绪知觉最常用的方法有面孔表情识别任务、面孔情绪强度判断任务(intensity judgment tasks),以及测量前注意无意识加工的后掩蔽任务(backward masking)等。与正常人相比,抑郁病人对悲伤面孔有更长的反应时,由于症状影响了他们对负性刺激的强度知觉,因此病人更多地将中性面孔解读为悲伤面孔,而将愉快面孔解读为中性面孔(Bourke,Douglas,& Porter,2010; Elliott,Zahn,Deakin,& Anderson,2011; Gollan,Pane,McCloskey,& Coccaro,2008)。这种偏向悲伤情绪的面孔知觉甚至会持续到病症的恢复期(Joormann & Gotlib,2007),增加了未来疾病复发的风险(Bouhuys,Geerts,& Gordijn,1999)。Delle等人总结了近年来抑郁症情绪知觉研究发现,病人对不愉快面孔有知觉偏向,并对愤怒面孔有过度反应(Delle-Vigne et al.,2014)。而与此相应的是,病人对快乐面孔的敏感度则降低：Jormann和 Gotlib让被试识别不同强度的面孔情绪,发现抑郁病人要在情绪强度很高的情况下才能正确识别快乐面孔,而对于悲伤和愤怒面孔则不需要如此(Joormann & Gotlib,2006); Yoon等人则采用二择一面孔情绪强度判断任务发现,抑郁病人很少将微快乐表情的情绪强度判断为比中性表情更高(Yoon,Joormann,& Gotlib,2009)。

在事件相关电位(event-related potential,ERP)研究中,Dai和Feng采用情绪强度评价任务发现,MDD病人对悲伤面孔有更大的P1和P2波幅,说明病人更容易被负性情绪面孔所唤起(Dai & Feng,2012)。Yang等人的研究发现,与积极靶刺激相比,当消极靶刺激出现时病人右后脑区的 P1潜伏期缩短,反映了一个非常早期的情绪知觉偏向(Yang,Zhu,Wang,Wu,& Yao,2011)。此外,Chang等人发现抑郁病人与面部表情有关的早期视觉失匹负波(visual mismatch negativity,vMMN)下降,表明抑郁病人在对表情信息的前注意加工中存在功能障碍(Chang,Xu,Shi,Zhang,& Zhao,2010)。

研究者普遍认为杏仁核涉及对情绪凸显刺激(包括面孔)的无意识和快速检测(Anderson & Phelps,2001; Morris,Öhman,& Dolan,1998; Whalen et al.,1998),而抑郁症患者对负性刺激的知觉偏向与杏仁核和腹内侧前额叶(ventromedial prefrontal cortex,VMPFC)的障碍有关,这些脑区涉及自下而上的情绪加工(Ochsner et al.,2004; Phillips,Drevets,Rauch,& Lane,2003)。该障碍表现为杏仁核对负性信息过度激活,且与 VMPFC的连接性(connectivity)发生改变(Fales et al.,2008)。

综上所述,大量行为学、电生理学研究均揭示了抑郁病人的心境一致性知觉偏向。该知觉偏向与杏仁核对负性情绪信息过度激活,以及杏仁核与VMPFC连接发生改变有关。

2 心境一致性注意偏向

研究情绪注意常用的任务包括负性情绪启动任务(negative affect priming task)、点探测任务(dot-probe task)、情绪词Stroop任务和Oddball任务等。与正常人相比,抑郁病人对负性刺激注意增加,对正性刺激注意减少,病人会选择与其心境一致的负性刺激进行编码,而过滤掉正性信息(Kellough,Beevers,Ellis,& Wells,2008; Peckham,McHugh,& Otto,2010)。在负性情绪启动任务中,抑郁病人表现出对悲伤面孔注意易化(attention facilitation)增加,即存在更强的情绪启动效应(affective priming effect) (Dai & Feng,2011a),而注意抑制减少(Dai & Feng,2011a; Goeleven,De Raedt,Baert,& Koster,2006)。对于后者,Everaert等人认为这是抑郁病人认知控制受损的表现之一(Everaert et al.,2012)。此外,病人对负性刺激尤其是悲伤刺激的注意偏向甚至会持续到抑郁症恢复期,表明抑郁病人对负性刺激的注意偏向是特质性而不是状态性的(Fritzsche et al.,2010)。值得一提的是,抑郁病人对负性刺激的注意偏向受到刺激呈现时长调节。Zhong等人在点探测任务中设置了100 ms和500 ms两种线索呈现时长,在100 ms条件下,抑郁病人倾向于把更多的注意分配到负性刺激上,但也有把少量注意分配到正性刺激上的趋势; 但在500 ms条件下,病人却存在难以避免注意负性刺激的趋势,也就是说刺激呈现时间越长,注意偏向就越有可能出现(Zhong,Zhu,Yi,Yao,& Atchley,2011)。因此,研究者认为刺激呈现时间较长的负性注意偏向并非是病人在负性刺激上分配了更多的注意资源,而是由于他们本身对负性刺激就存在注意解除困难(de Raedt &Koster,2010; Yoon et al.,2009)。

在ERP研究中,情绪词Stroop任务研究发现负性情绪词对 MDD病人有更强的干扰效应,即对消极信息的注意抑制能力受损,体现为病人的N1波幅降低,顶叶的N450波幅升高(Dai & Feng,2011b)。一些研究者认为：由于病人注意分心作用的增加,这种注意抑制能力的受损会使得早期认知加工阶段注意资源变少,表现为在执行负性情感启动任务时,负性刺激在病人身上诱发了更低P2波幅(Yao et al.,2010)。这些研究从ERP角度证明了先前行为学的结果,即抑郁病人对负性刺激的注意抑制减少,那么当病人注意正性刺激时,相关ERP结果又能提供哪些启示呢？前面提及的情绪词Stroop任务的ERP结果就发现正性刺激出现时病人的P1波幅降低,这意味着他们对积极刺激给予较少的注意资源(Dai & Feng,2011b)。在一项 Oddball任务中,正性靶刺激在病人额区诱发出更大的P2成分,作者认为此结果反映了病人早期阶段的情绪加工偏差可能包含有对正性刺激的注意缺陷(Yang et al.,2011)。Zhong等人点探测实验的ERP结果也发现：当正性-中性图片的有效试次呈现时,与无效试次相比,病人没有像正常人那样出现更大的 P1波,且正性-中性图片的注意偏向分数为负值(正常人则为正值),表明抑郁病人缺少对正性刺激的注意(Zhong et al.,2011)。此外,ERP研究还证明了行为学支持的注意解除困难效应能持续到抑郁症的恢复期,比如当一个任务需要个体把注意从负性面孔中解除出来时,与正常人相比抑郁症恢复期个体反应更慢,且 N450波幅降低,说明抑郁症的注意解除困难也是特质性的(Vanderhasselt et al.,2012)。

脑成像研究发现,与正常人相比抑郁症病人右侧腹外侧前额叶(ventral lateral prefrontal cortex,VLPFC)、右侧背外侧前额叶(dorsal lateral prefrontal cortex,DLPFC)和右侧顶上皮质对负性刺激激活减少(Beevers,Clasen,Stice,& Schnyer,2010;Fales et al.,2008),这些区域的活动减退可能是促成病人对负性刺激注意解除困难的原因(Disner,Beevers,Haigh,& Beck,2011)。当正常人成功地抑制了对积极刺激的注意时,他们的前扣带回喙部(rostral anterior cingulate cortex,rACC)比抑郁病人有更大的激活; 相反的,当抑郁病人成功地抑制了对消极刺激的注意时,他们的相应部位比正常人有更大激活(Elliott,Rubinsztein,Sahakian,&Dolan,2002; Eugène,Joormann,Cooney,Atlas,&Gotlib,2010; Mitterschiffthaler et al.,2008)。这说明正常个体需要更多的认知资源对积极刺激进行注意解除,而抑郁个体则需要更多的认知资源对消极刺激进行注意解除(Disner et al.,2011)。在一个情绪线索任务中,当要求被试的注意力从无关情绪线索转移时,症状越严重的病人其外侧前额区与顶区激活越弱,而非情绪线索条件下则无此效应,说明抑郁病人在对情绪信息进行认知控制的脑区上出现了加工障碍(Beevers et al.,2010)。已知 rACC与自我参照加工有关(Nejad,Fossati,&Lemogne,2013)。研究发现抑郁病人的rACC在负性自我参照加工中有所激活,且激活程度与症状的严重程度有显著相关(Wagner et al.,2013)。事实上,抑郁病人的自我聚焦(self-focus),即对自我的内部注意是增加的,反映了病人的自我注意偏向(Nejad et al.,2013)。Disner等人在其认知模型中总结：抑郁个体在刺激选择(与 DLPFC功能降低有关)、对负性刺激的注意解除(与DLPFC和前扣带回功能降低有关)以及映射到其他潜在适应性刺激的注视转移(gaze shift) (与顶上皮层功能降低有关)等认知功能中缺乏效率(Disner et al.,2011)。

综上所述,抑郁症患者对负性刺激的注意偏向表现在对负性刺激注意增加且抑制减少,对正性刺激注意减少,以及对负性刺激的注意解除困难上,该偏向与额区、顶区以及前扣带回功能异常有关。

3 心境一致性记忆偏向

抑郁症患者以外显长时记忆偏向为标志性认知偏向(Everaert et al.,2012)。它一方面表现为患者对负性信息有回忆偏向(Mathews & MacLeod,2005),且在回忆与自我相关的负性信息时,这种偏向效应表现得更强(Wisco,2009)。另一方面则表现为患者不具备正常人那样的对积极事件的正性记忆偏向(Harmer et al.,2009)。然而除了外显层面,负性记忆偏向在内隐记忆层面也有表现。抑郁病人在检测阈下呈现的负性词时的速度比正常人更快(Phillips,Hine,& Thorsteinsson,2010),同时在曾有抑郁史(formerly depressed)个体中也出现了此种效应(Romero,Sanchez,& Vazquez,2014)。元分析(meta-analysis)发现,抑郁病人对负性信息存在内隐回忆偏向,而正常人则对正性信息有内隐回忆偏向; 病人在编码自我相关信息时,这种偏负性的内隐回忆更加明显(Gaddy & Ingram,2014)。抑郁症的负性记忆偏向还存在于错误记忆之中。研究发现病人在错误记忆任务中比正常人更倾向于把负性情境下的新词误认为是旧词; 同样,自我相关性因素在病人的错误记忆偏向中占有重要位置(Wittekind et al.,2014)。

近年来,抑郁症患者的工作记忆成为心境一致认知偏向研究的热点。工作记忆是一个容量有限的系统(Baddeley,1996),它在情绪调节中维持与任务相关的情绪内容而排除与任务不相关的情绪内容,并且可以影响积极和消极情绪(Vanderhasselt et al.,2012)。然而,大量研究表明抑郁病人存在从工作记忆中消除无关负性想法或记忆的困难(Berman et al.,2011; Foland-Ross et al.,2013;Joormann & Gotlib,2008; Levens & Gotlib,2010;Yoon,LeMoult,& Joormann,2014)。作为认知控制受损的又一大表现,患者在工作记忆涉及转移(shifting)和更新(updating)情绪及非情绪表征的过程中也存在异常(Lissnyder,Koster,& de Raedt,2012; Lo & Allen,2011)。这导致太多的负性信息在抑郁病人的工作记忆容量中没有得到及时转移和更新且一直堆积下去,使得病人沉浸在负性情绪内容中并表现出对负性无关信息的提取增加,因而维持了抑郁心境(Yoon et al.,2014)。有意思的是,当无关信息为正性时,抑郁病人并不存在工作记忆解除困难,相反对它的解除比正常人更快(Levens & Gotlib,2010)。

脑成像研究发现,当编码负性刺激时,抑郁病人在右侧杏仁核的激活上比正常人更大,且杏仁核与海马及尾状核-壳核的功能连接(functional connectivity)也更强,病人右侧杏仁核在编码负性刺激时的活动与同侧海马及尾状核-壳核的活动有更高的相关(Hamilton & Gotlib,2008)。Arnold等人采用弥散张量成像对恢复期抑郁病人进行研究,也发现杏仁核与海马、小脑、脑干的连接增强,并认为这可能导致情绪记忆偏向; 他们还发现这些病人内侧前额叶皮质(medial prefrontal cortex,mPFC)的神经元密度减少,可能反映了自上而下加工的减弱,即额区损伤弱化了对杏仁核的调节,使得杏仁核向海马等皮质下区域的输出失调,因而间接诱发了负性记忆偏向(Arnold et al.,2012)。Arnold等人的另一个研究也说明情绪性记忆偏向相关的神经改变会持续到抑郁症的恢复期(Arnold et al.,2011),因此这种神经改变可能是抑郁复发的原因(Arnold et al.,2012)。Disner等人在其认知模型中总结：抑郁症的记忆偏向可能起因于编码负性刺激时杏仁核活动的增加,而回忆时海马(负责情节记忆)、尾状核-壳核活动(负责技能学习)增加(Disner et al.,2011)。此外,对于工作记忆中无关负性信息解除困难现象,功能性核磁共振成像(functional magnetic resonance imaging,fMRI)研究发现,当要求被试把负性词从工作记忆中移除时,病人的前扣带回、顶上小叶以及双侧脑岛都有更大激活,相反的是,当把正性词从工作记忆中移除时正常人的相应脑区有更大激活(Foland-Ross et al.,2013)。此外,抑郁病人在进行工作记忆任务时存在皮质-边缘系统-皮质下神经环路的功能异常,主要表现为额区、前扣带回、顶叶、颞叶和枕叶等脑区的异常激活,但受限于被试的异质性和研究方法的不同,目前尚未得到一致的激活模式(Wang et al.,2015)。

综上所述,抑郁病人更容易回忆与自己抑郁心境一致的内容,这种记忆偏向在内隐记忆、错误记忆中也都有表现,负性内容一旦与自我相关性结合还会增强该记忆偏向效应。该记忆偏向主要由边缘系统(杏仁核、海马)调节,但在皮层区也有激活异常。此外,病人在消除、转换和更新工作记忆中的负性信息时还存在困难,这是认知控制损伤的一大表现。

4 心境一致性解释偏向

Beck的负性图式模型和新近的抑郁认知理论都提到抑郁症与解释偏向(interpretation bias)有关(Beck,2008; Mathews & MacLeod,2005),即抑郁症患者倾向于消极地解释模棱两可事件。早期研究曾证实了该偏向的存在(Butler & Mathews,1983),但也有研究并未发现这一现象(Bisson &Sears,2007; Lawson & MacLeod,1999)。然而Lawson等人用情绪模棱两可文字诱发意象,通过测量被试的惊反应(the startle response)大小发现了解释偏向在抑郁个体身上的存在证据,并认为解释偏向是抑郁的一个认知易感性因子(Lawson,MacLeod,& Hammond,2002)。Rude等人则在大学生群体中发现解释偏向的大小能预测后续抑郁症状的严重程度(Rude,Wenzlaff,Gibbs,Vane,&Whitney,2002)。

目前仅发表了一篇探讨抑郁症解释偏向的ERP研究。该研究使用了语法判断任务(The grammar decision task)作为实验任务,在听完模棱两可句子的前半部分后,被试会看到不同情绪类别的句尾词,然后判断该词在所听到的句子中是符合语法规则的(grammatical)还是不符合语法规则的(non-grammatical) (Moser,Huppert,Foa,& Simons,2012)。结果发现正性句尾词和负性句尾词在抑郁病人身上所诱发的 N4波幅无显著差异,表明病人对结尾的正性或负性有同样的期待,即不存在正性解释偏向; 回归分析还发现抑郁症状与 N4解释偏向效应有关,这为抑郁症存在负性解释偏向提供了部分证据(Moser et al.,2012)。

综上所述,抑郁症患者的负性解释偏向虽然得到一些理论模型的支持,且已存在部分行为学与电生理学证据,然而该领域相关研究并未达成一致的结论,因此该偏向及有关的神经机制值得深入挖掘。

5 认知偏向的三个特点及脑机制

根据以上研究,结合 Rottenberg等人提出的负性增强假设(negative potentiation hypothesis)(该观点认为抑郁病人对负性情绪刺激反应敏感)与正性衰减假设(positive attenuation hypothesis)(该观点认为抑郁病人对正性情绪刺激反应迟钝)(Rottenberg,Gross,& Gotlib,2005),我们总结出抑郁症心境一致性认知偏向存在三个主要特点,且推断该认知偏向是这些特点背后的脑机制协同作用的产物。(1)加工偏向负性：该特点在知觉、注意、记忆以及解释等认知环节层面均存在,而原因可能是大脑杏仁核对负性信息存在过度激活。杏仁核的功能包括将注意指向情绪信息、易化情绪记忆以及产生自主的情绪反应(Pessoa,2010)。当抑郁症患者对情绪性刺激进行知觉、评估和反应时,负性情绪刺激(如悲伤和恐惧面孔)能使大脑自下而上的反应增强(杏仁核、梭状回等脑区过度激活) (Arnone et al.,2012; Monk et al.,2008; 廖成菊,冯正直,2010),甚至在无意识条件下也是如此(Suslow et al.,2010; Victor,Furey,Fromm,Öhman,& Drevets,2010); (2)加工偏离正性或积极偏向缺失：该特点与负性偏向一样,也存在于抑郁病人的各个认知环节中,而原因则是纹状体对正性信息激活减弱,这可能是抑郁症核心症状之一——快感缺失的神经机制(Epstein et al.,2006)。众所周知,纹状体是奖赏环路的重要组成部分,与积极情绪的加工有关(Groenewold,Opmeer,de Jonge,Aleman,& Costafreda,2013),而 MDD病人的奖赏环路以纹状体和边缘区活动减少以及额区激活增加为特征(Demenescu et al.,2011)。Heller等人对抑郁病人进行2个月的药物治疗发现,病人伏隔核激活越大以及脑内额中回-纹状体环路连接增加得越多,病人体验到的积极情绪也越多。作者认为抑郁症可能部分源于伏隔核持续活动和额区-纹状体连接性的缺失(Heller et al.,2013); (3)认知控制的损伤：表现为抑郁病人对负性信息存在抑制和解除困难,这在注意和工作记忆环节均有体现。原因是抑郁病人负责认知控制的脑区激活模式异常,比如额区对负性表情激活减少,而对正性表情激活增加,这可能反映了由心境不一致刺激所触发的情绪调节需要的增加(Demenescu et al.,2011)。DLPFC和前扣带回对认知控制的缺乏可能危害自上而下的情绪监控,从而使得患者大脑调节杏仁核反应的能力减弱(Beck,2008; Pizzagalli,2011)。此外,病人对于未知情绪效价的事件的负性预测偏向也可能是认知控制损伤所致。Herwig等人让被试根据线索预期并知觉具有情绪效价以及未知情绪效价的图片,结果发现在预期未知情绪效价的情绪图片时,抑郁病人在DLPFC和mPFC等脑区的神经激活模式与预期负性情绪图片时相同(Herwig et al.,2010)。

6 现阶段有待回答的问题与未来展望

抑郁症人群的心境一致性偏向在认知加工的各个环节(知觉、注意、记忆、解释)都有发生。根据目前的相关研究,我们发现此认知偏向的特点为偏向负性刺激、偏离正性刺激,以及认知控制受损。该认知偏向在脑成像研究中表现为边缘系统(包括杏仁核、海马等)对负性刺激的异常激活,纹状体对正性刺激激活不足,以及额区对皮质下区域认知控制的减弱,总体反映了自下而上加工的增强以及自上而下加工的减弱。然而,抑郁症人群心境一致性偏向的研究仍有诸多问题有待回答。总结起来主要有以下三点：

第一,各环节的认知偏向间是否存在联系？Everaert等人认为现阶段研究的一个主要局限是抑郁病人的认知偏向被单独地、孤立地在相当特定的信息加工阶段内进行研究(Everaert et al.,2012)。他们的研究已证明,不同的认知偏向(知觉、解释、注意、认知控制)是相互联系的,但哪一种或哪几种认知偏向对于后续症状发作更具有预测力仍然不得而知(Everaert et al.,2012)。当前已有研究表明抑郁症的注意偏向和记忆偏向具有密切的联系,注意偏向的改变会影响情绪刺激的精细加工,并且是心境一致性记忆偏向的原因之一(Blaut,Paulewicz,Szastok,Prochwicz,& Koster,2013)。解释偏向也会影响外显记忆,积极解释偏向训练还可能是改变负性记忆偏向的一个有效手段(Salemink,Hertel,& Mackintosh,2010; Tran,Hertel,& Joormann,2011)。那么,各认知偏向之间若有联系,这种联系又是什么样的关系,是序列关系还是平行关系？迄今为止这些问题还没有得到有效解决。

第二,心境一致性认知偏向与抑郁症的关系是什么？具体而言,是认知偏向导致了抑郁症,还是抑郁症导致了认知偏向(戴琴,冯正直,2008)？研究表明,认知偏向是抑郁症状产生、持续和发展的重要原因之一(Taylor & John,2004)。这么看来似乎是认知偏向导致了抑郁症,但上述很多研究已经证明：恢复期个体抑郁症状虽早已消失,却仍然存在认知偏向和相应神经变化。这该作何解释？那可以认为是抑郁症导致了认知偏向吗？恐怕不能。Singh等人通过考察有家族抑郁风险的儿童发现,认知偏向以及结构和功能性的神经改变早在抑郁症状发作之前就已出现(Singh& Gotlib,2014)。与健康母亲的健康女儿相比,罹患抑郁症母亲的健康女儿会选择性地注视负性情绪面孔,表现出注意偏向(Joormann,Talbot,&Gotlib,2007),且会把模棱两可的词语和故事解释得更消极,表现出解释偏向(Dearing & Gotlib,2009)。这些患病家庭的健康儿童在产生认知偏向的同时还伴随有相应的神经改变：当出现消极情绪时,病人母亲的女儿在涉及消极情绪体验的脑区(杏仁核与 VLPFC)比正常母亲的女儿有更大的激活; 相反在回忆积极情绪时,正常母亲的女儿在涉及对情绪自上而下调节的区域(DLPFC与背侧前扣带回)比病人母亲的女儿有更大的激活(Joormann,Cooney,Henry,& Gotlib,2012)。由此可知这些来自有抑郁风险家族的儿童虽并未被诊断有抑郁症,却也会出现抑郁症所特有的认知偏向和相应脑激活改变,意味着认知偏向并非由抑郁症直接引起。目前看来,这个问题相当复杂,国内学者暂把认知偏向视作抑郁症的一个特征(戴琴,冯正直,2008)。

第三,如何解决研究结果的不一致？在抑郁症认知偏向的诸研究中,结果的不一致时有发现。例如,对抑郁症工作记忆的脑成像研究通常发现病人额叶神经环路的功能失调(Wang et al.,2015),同样采用与工作记忆相关的任务,有研究发现病人 DLPFC激活增强(Matsuo et al.,2007;Walter,Wolf,Spitzer,& Vasic,2007),也有发现该区域激活减弱(Garrett et al.,2011; Kerestes et al.,2012),甚至还有研究未发现该脑区被激活(Sandström et al.,2012)。多数研究者把结果不一致的问题归结为被试和实验任务的异质性,以及认知本身的复杂性。除此之外,我们认为还有两个重要原因不容忽视：其一是实验范式的有效性。例如一个元分析研究发现,在抑郁症注意偏向的测量上,点探测范式比情绪 Stroop范式更有效,且效果量更大(Peckham et al.,2010)。其二,大部分研究只注重刺激材料的情绪效价,却忽视了刺激的自我相关性。事实上,抑郁症不仅仅与负性偏向有关,还与增加的自我聚焦(self-focus)有关(Nejad et al.,2013)。抑郁病人加工与自我有关的负性刺激时,认知偏向会增强(Gaddy & Ingram,2014)。部分研究极有可能让自我相关因素混淆到实验刺激中,造成了与控制严格的实验研究所不一致的结果。

因此,未来研究可以从以下三个方向开展。首先,如前所述,虽然在知觉、注意、记忆和认知解释每个层面对抑郁症的认知偏向都有不少研究,但对两个或三个环节之间的综合性研究甚少,因此难以对抑郁症的认知偏向形成一个整体的认识。所以今后对抑郁病人的知觉与注意、记忆以及解释四个偏向进行综合研究是很有必要的。其次,需要进行纵向研究以探讨认知偏向与抑郁症的因果关系,以此确定认知偏向究竟是抑郁症的预测因子还是诊断标准之一。最后,亟需一个标准化的实验流程以尽量减少方法学、人口学上的变异,目前已有研究者在此方面作出了有益尝试。例如Korgaonkar等人在fMRI中采用了标准化的成套测验和成像协议(imaging protocols),以此控制方法学和样本所产生的变异,该研究发现,抑郁病人在工作记忆更新和有意识的负性情绪加工期间,DLPFC的激活减少; 在工作记忆任务和反应抑制任务中背内侧前额叶皮质(dorsomedial prefrontal cortex,DMPFC)的激活增大; 在有意识的正性情绪加工期间,DMPFC激活减少(Korgaonkar,Grieve,Etkin,Koslow,& Williams,2013)。此外,检测各研究范式的效果量,尽可能选择大效果量的实验范式,排除刺激材料自我相关性对研究结果的干扰,进而改善目前研究结论不一致的状况。

戴琴,冯正直. (2008). 抑郁患者的注意偏向.心理科学进展,16(2),260–265.

廖成菊,冯正直. (2010). 抑郁症情绪加工与认知控制的脑机制.心理科学进展,18(2),282–287.

杨娟,张小崔,姚树桥. (2014). 抑郁症认知偏向的神经机制研究进展.中国临床心理学杂志,22(5),788–791.

Anderson,A. K.,& Phelps,E. A. (2001). Lesions of the human amygdala impair enhanced perception of emotionally salient events.Nature,411(6835),305–309.

Arnold,J. F.,Fitzgerald,D. A.,Fernández,G.,Rijpkema,M.,Rinck,M.,Eling,P. A. T. M.,… Tendolkar,I. (2011).Rose or black-coloured glasses? Altered neural processing of positive events during memory formation is a trait marker of depression.Journal of Affective Disorders,131(1-3),214–223.

Arnold,J. F.,Zwiers,M. P.,Fitzgerald,D. A.,van Eijndhoven,P.,Becker,E. S.,Rinck,M.,… Tendolkar,I.(2012). Fronto-limbic microstructure and structural connectivity in remission from major depression.Psychiatry Research,204(1),40–48.

Arnone,D.,McKie,S.,Elliott,R.,Thomas,E. J.,Downey,D.,Juhasz,G.,…,Anderson,I. M. (2012). Increased amygdala responses to sad but not fearful faces in major depression: Relation to mood state and pharmacological treatment.American Journal of Psychiatry,169(8),841–850.

Baddeley,A. (1996). Exploring the central executive.The Quarterly Journal of Experimental Psychology: Section A,49(1),5–28.

Baert,S.,Koster,E. H. W.,& de Raedt,R. (2011).Modification of information-processing biases in emotional disorders: Clinically relevant developments in experimental psychopathology.International Journal of C ognitive Therapy,4(2),208–222.

Beck,A. T. (1967).Depression: Clinical,experimental,and theoretical aspects(Vol. 32). Pennsylvania: University of Pennsylvania Press.

Beck,A. T. (2008). The evolution of the cognitive model of depression and its neurobiological correlates.American Journal of Psychiatry,165(8),969–977.

Beevers,C. G.,Clasen,P.,Stice,E.,& Schnyer,D. (2010).Depression symptoms and cognitive control of emotion cues: A functional magnetic resonance imaging study.Neuroscience,167(1),97–103.

Berman,M. G.,Nee,D. E.,Casement,M.,Kim,H. S.,Deldin,P.,Kross,E.,… Jonides,J. (2011). Neural and behavioral effects of interference resolution in depression and rumination.Cognitive,Affective,&B ehavioral Neuroscience,11(1),85–96.

Bisson,M. A. S.,& Sears,C. R. (2007). The effect of depressed mood on the interpretation of ambiguity,with and without negative mood induction.Cognition &Emotion,21,614–645.

Blaut,A.,Paulewicz,B.,Szastok,M.,Prochwicz,K.,&Koster,E. (2013). Are attentional bias and memory bias for negative words causally related?Journal of Behavior Therapy and Experimental Psychiatry,44(3),293–299.

Bouhuys,A. L.,Geerts,E.,& Gordijn,M. C. M. (1999).Depressed patients’ perceptions of facial emotions in depressed and remitted states are associated with relapse:A longitudinal study.The Journal of Nervous and Mental Disease,187,595–692.

Bourke,C.,Douglas,K.,& Porter,R. (2010). Processing of facial emotion expression in major depression: A review.Australian and New Zealand Journal of Psychiatry,44(8),681–696.

Butler,G.,& Mathews,A. (1983). Cognitive processes in anxiety.Advances in Behaviour Research and Therapy,5,51–62.

Chang,Y.,Xu,J.,Shi,N.,Zhang,B. W.,& Zhao,L. (2010).Dysfunction of processing task-irrelevant emotional faces in major depressive disorder patients revealed by expressionrelated visual MMN.Neuroscience Letters,472(1),33–37.

Dai,Q.,& Feng,Z. Z. (2011a). Dysfunctional distracter inhibition and facilitation for sad faces in depressed individuals.Psychiatry Research,190(2-3),206–211.

Dai,Q.,& Feng,Z. Z. (2011b). Deficient interference inhibition for negative stimuli in depression: An event-related potential study.Clinical Neurophysiology,122(1),52–61.

Dai,Q.,& Feng,Z. Z. (2012). More excited for negative facial expressions in depression: Evidence from an event-related potential study.Clinical N europhysiology,123(11),2172–2179.

De Lissnyder,E.,Koster,E. H. W.,& de Raedt,R. (2012).Emotional interference in working memory is related to rumination.Cognitive Therapy and Research,36(4),348–357.

De Raedt,R.,& Koster,E. H. W. (2010). Understanding vulnerability for depression from a cognitive neuroscience perspective: A reappraisal of attentional factors and a new conceptual framework.Cognitive,Affective,& Behavioral Neuroscience,10(1),50–70.

Dearing,K. F.,& Gotlib,I. H. (2009). Interpretation of ambiguous information in girls at risk for depression.Journal of Abnormal Child Psychology,37,79–91.

Delle-Vigne,D.,Wang,W.,Kornreich,C.,Verbanck,P.,&Campanella,S. (2014). Emotional facial expression processing in depression: Data from behavioral and event-related potential studies.Neurophysiologie Cl inique-Clinical Neurophysiology,44(2),169–187.

Demenescu,L. R.,Renken,R.,Kortekaas,R.,van Tol,M. J.,Marsman,J. B. C.,van Buchem,M. A.,… Aleman,A.(2011). Neural correlates of perception of emotional facial expressions in out-patients with mild-to-moderate depression and anxiety. A multicenter fMRI study.Psychological Medicine,41(11),2253–2264.

Disner,S. G.,Beevers,C. G.,Haigh,E. A. P.,& Beck,A. T.(2011). Neural mechanisms of the cognitive model of depression.Nature Reviews Neuroscience,12(8),467–477.

Elliott,R.,Rubinsztein,J. S.,Sahakian,B. J.,& Dolan,R. J.(2002). The neural basis of mood-congruent processing biases in depression.Archives of G eneral P sychiatry,59(7),597–604.

Elliott,R.,Zahn,R.,Deakin,J. F. W.,& Anderson,I. M.(2011). Affective cognition and its disruption in mood disorders.Neuropsychopharmacology,36(1),153–182.

Epstein,J.,Pan,H.,Kocsis,J. H.,Yang,Y. H.,Butler,T.,Chusid,J.,… Silbersweig,D. A. (2006). Lack of ventral striatal response to positive stimuli in depressed versus normal subjects.American Journal of Psychiatry,163(10),1784–1790.

Eugène,F.,Joormann,J.,Cooney,R. E.,Atlas,L. Y.,&Gotlib,I. H. (2010). Neural correlates of inhibitory deficits in depression.Psychiatry Research,181(1),30–35.

Everaert,J.,Koster,E. H. W.,& Derakshan,N. (2012). The combined cognitive bias hypothesis in depression.Clinical Psychology Review,32(5),413–424.

Fales,C. L.,Barch,D. M.,Rundle,M. M.,Mintun,M. A.,Snyder,A. Z.,Cohen,J. D.,… Sheline,Y. I. (2008).Altered emotional interference processing in affective and cognitive-control brain circuitry in major depression.Biological Psychiatry,63(4),377–384.

Foland-Ross,L. C.,Hamilton,J. P.,Joormann,J.,Berman,M. G.,Jonides,J.,& Gotlib,I. H. (2013). The neural basis of difficulties disengaging from negative irrelevant material in major depression.Psychological Science,24(3),334–344.

Fritzsche,A.,Dahme,B.,Gotlib,I. H.,Joormann,J.,Magnussen,H.,Watz,H.,… von Leupoldt,A. (2010).Specificity of cognitive biases in patients with current depression and remitted depression and in patients with asthma.Psychological Medicine,40(5),815–826.

Gaddy,M. A.,& Ingram,R. E. (2014). A meta-analytic review of mood-congruent implicit memory in depressed mood.Clinical Psychology Review,34(5),402–416.

Garrett,A.,Kelly,R.,Gomez,R.,Keller,J.,Schatzberg,A.F.,& Reiss,A. L. (2011). Aberrant brain activation during a working memory task in psychotic major depression.American Journal of Psychiatry,168(2),173–182.

Goeleven,E.,De Raedt,R.,Baert,S.,& Koster,E. H. W.(2006). Deficient inhibition of emotional information in depression.Journal of Affective Disorders,93(1-3),149–157.

Gollan,J. K.,Pane,H. T.,McCloskey,M. S.,& Coccaro,E.F. (2008). Identifying differences in biased affective information processing in major depression.Psychiatry Research,159(1-2),18–24.

Groenewold,N. A.,Opmeer,E. M.,de Jonge,P.,Aleman,A.,& Costafreda,S. G. (2013). Emotional valence modulates brain functional abnormalities in depression: Evidence from a meta-analysis of fMRI studies.Neuroscience and Biobehavioral Reviews,37(2),152–163.

Hamilton,J. P.,& Gotlib,I. H. (2008). Neural substrates of increased memory sensitivity for negative stimuli in major depression.Biological Psychiatry,63(12),1155–1162.

Harmer,C. J.,O'Sullivan,U.,Favaron,E.,Massey-Chase,R.,Ayres,R.,Reinecke,A.,… Cowen,P. J. (2009). Effect of acute antidepressant administration on negative affective bias in depressed patients.American Journal of Psychiatry,166(10),1178–1184.

Heller,A. S.,Johnstone,T.,Light,S. N.,Peterson,M. J.,Kolden,G. G.,Kalin,N. H.,et al. (2013). Relationships between changes in sustained fronto-striatal connectivity and positive affect in major depression resulting from antidepressant treatment.American Journal of Psychiatry,170(2),197–206.

Herwig,U.,Brühl,A. B.,Kaffenberger,T.,Baumgartner,T.,Boeker,H.,& Jäncke,L. (2010). Neural correlates of‘pessimistic’ attitude in depression.Psychological Medicine,40(5),789–800.

Joormann,J.,Cooney,R. E.,Henry,M. L.,& Gotlib,I. H.(2012). Neural correlates of automatic mood regulation in girls at high risk for depression.Journal of A bnormalPsychology,121(1),61–72.

Joormann,J.,Gilbert,K.,& Gotlib,I. H. (2010). Emotion identification in girls at high risk for depression.Journal of Child Psychology and Psychiatry,51(5),575–582.

Joormann,J.,& Gotlib,I. H. (2006). Is this happiness I see?Biases in the identification of emotional facial expressions in depression and social phobia.Journal of Abnormal Psychology,115,705–714.

Joormann,J.,& Gotlib,I. H. (2007). Selective attention to emotional faces following recovery from depression.Journal of Abnormal Psychology,116(1),80–85.

Joormann,J.,& Gotlib,I. H. (2008). Updating the contents of working memory in depression: Interference from irrelevant negative material.Journal of Abnormal Psychology,117(1),182–192.

Joormann,J.,Talbot,L.,& Gotlib,I. H. (2007). Biased processing of emotional information in girls at risk for depression.Journal of A bnormal Psychology,116(1),135–143.

Kellough,J. L.,Beevers,C. G.,Ellis,A. J.,& Wells,T. T.(2008). Time course of selective attention in clinically depressed young adults: An eye tracking study.Behaviour Research and Therapy,46(11),1238–1243.

Kerestes,R.,Ladouceur,C. D.,Meda,S.,Nathan,P. J.,Blumberg,H. P.,Maloney,K.,… Phillips,M. L. (2012).Abnormal prefrontal activity subserving attentional control of emotion in remitted depressed patients during a working memory task with emotional distracters.Psychological Medicine,42(1),29–40.

Korgaonkar,M. S.,Grieve,S. M.,Etkin,A.,Koslow,S. H.,&Williams,L. M. (2013). Using standardized fMRI protocols to identify patterns of prefrontal circuit dysregulation that are common and specific to cognitive and emotional tasks in major depressive disorder: First wave results from the iSPOT-D study.Neuropsychopharmacology,38(5),863–871.

Lawson,C.,& MacLeod,C. (1999). Depression and the interpretation of ambiguity.Behaviour R esearch and Therapy,37(5),463–474.

Lawson,C.,MacLeod,C.,& Hammond,G. (2002).Interpretation revealed in the blink of an eye: Depressive bias in the resolution of ambiguity.Journal of Abnormal Psychology,111(2),321–328.

Levens,S. M.,& Gotlib,I. H. (2010). Updating positive and negative stimuli in working memory in depression.Journal of Experimental Psychology: General,139(4),654–664.

Lo,B. C. Y.,& Allen,N. B. (2011). Affective bias in internal attention shifting among depressed youth.Psychiatry Research,187(1-2),125–129.

Mathews,A.,& MacLeod,C. (2005). Cognitive vulnerability to emotional disorders.Annual Review of Clinical Psychology,1,167–195.

Matsuo,K.,Glahn,D. C.,Peluso,M. A. M.,Hatch,J. P.,Monkul,E. S.,Najt,P.,… Soares,J. C. (2007). Prefrontal hyperactivation during working memory task in untreated individuals with major depressive disorder.Molecular Psychiatry,12(2),158–166.

Mitterschiffthaler,M. T.,Williams,S. C.,Walsh,N. D.,Cleare,A. J.,Donaldson,C.,Scott,J.,& Fu,C. H. (2008).Neural basis of the emotional Stroop interference effect in major depression.Psychological Medicine,38(2),247–256.

Monk,C. S.,Klein,R. G.,Telzer,E. H.,Schroth,E. A.,Mannuzza,S.,Moulton,J. L.,… Ernst,M. (2008).Amygdala and nucleus accumbens activation to emotional facial expressions in children and adolescents at risk for major depression.American Journal of Psychiatry,165(1),90–98.

Morris,J. S.,Öhman,A.,Dolan,R. J. (1998). Conscious and unconscious emotional learning in the human amygdala.Nature,393(6684),467–470.

Moser,J. S.,Huppert,J. D.,Foa,E. B.,& Simons,R. F.(2012). Interpretation of ambiguous social scenarios in social phobia and depression: Evidence from event-related brain potentials.Biological Psychology,89(2),387–397.

Nejad,A. B.,Fossati,P.,& Lemogne,C. (2013).Self-referential processing,rumination,and cortical midline structures in major depression.Frontiers in Human Neuroscience,7,666.

Ochsner,K. N.,Ray,R. D.,Cooper,J. C.,Robertson,E. R.,Chopra,S.,Gabrieli,J. D. E.,& Gross,J. J. (2004). For better or for worse: Neural systems supporting the cognitive down- and up-regulation of negative emotion.NeuroImage,23(2),483–499.

Peckham,A. D.,McHugh,R. K.,& Otto,M. W. (2010). A meta-analysis of the magnitude of biased attention in depression.Depression and Anxiety,27(12),1135–1142.

Pessoa,L. (2010). Emotion and cognition and the amygdala:From “what is it?” to “what’s to be done?”.Neuropsychologia,48,3416–3429.

Phillips,M. L.,Drevets,W. C.,Rauch,S. L.,& Lane,R.(2003). Neurobiology of emotion perception I: The neural basis of normal emotion perception.Biological Psychiatry,54(5),504–514.

Phillips,W. J.,Hine,D. W.,& Thorsteinsson,E. B. (2010).Implicit cognition and depression: A meta-analysis.Clinical Psychology Review,30(6),691–709.

Pizzagalli,D. A. (2011). Frontocingulate dysfunction in depression: Toward biomarkers of treatment response.Neuropsychopharmacology,36(1),183–206.

Roiser,J. P.,Elliott,R.,& Sahakian,B. J. (2012). Cognitive mechanisms of treatment in depression.Neuropsychopharmacology,37(1),117–136.

Romero,N.,Sanchez,A.,& Vazquez,C. (2014). Memory biases in remitted depression: The role of negative cognitions at explicit and automatic processing levels.Journal of Behavior Therapy and Experimental Psychiatry,45(1),128–135.

Rottenberg,J.,Gross,J. J.,& Gotlib,I. H. (2005). Emotion context insensitivity in major depressive disorder.Journal of Abnormal Psychology,114(4),627–639.

Rude,S. S.,Wenzlaff,R. M.,Gibbs,B.,Vane,J.,& Whitney,T. (2002). Negative processing biases predict subsequent depressive symptoms.Cognition & Emotion,16,423–440.

Salemink,E.,Hertel,P.,& Mackintosh,B. (2010).Interpretation training influences memory for prior interpretations.Emotion,10(6),903–907.

Sandström,A.,Säll,R.,Peterson,J.,Salami,A.,Larsson,A.,Olsson,T.,… Nyberg,L. (2012). Brain activation patterns in major depressive disorder and work stress-related long-term sick leave among Swedish females.Stress,15(5),503–513.

Scher,C. D.,Ingram,R. E.,& Segal,Z. V. (2005). Cognitive reactivity and vulnerability: Empirical evaluation of construct activation and cognitive diatheses in unipolar depression.Clinical Psychology Review,25(4),487–510.

Singh,M. K.,& Gotlib,I. H. (2014). The neuroscience of depression: Implications for assessment and intervention.Behaviour Research and Therapy,62,60–73.

Suslow,T.,Konrad,C.,Kugel,H.,Rumstadt,D.,Zwitserlood,P.,Schöning,S.,… Dannlowski,U. (2010).Automatic mood-congruent amygdala responses to masked facial expressions in major depression.Biological Psychiatry,67(2),155–160.

Taylor,J. L.,& John,C. H. (2004). Attentional and memory bias in persecutory delusions and depression.Psychopathology,37(5),233–241.

Tran,T. B.,Hertel,P. T.,& Joormann,J. (2011). Cognitive bias modification: Induced interpretive biases affect memory.Emotion,11(1),145–152.

Vanderhasselt,M. A.,De Raedt,R.,Dillon,D. G.,Dutra,S.J.,Brooks,N.,& Pizzagalli,D. A. (2012). Decreased cognitive control in response to negative information in patients with remitted depression: An event-related potential study.Journal of Psychiatry & Neuroscience,37(4),250–258.

Victor,T. A.,Furey,M. L.,Fromm,S. J.,Öhman,A.,&Drevets,W. C. (2010). Relationship between amygdala responses to masked faces and mood state and treatment in major depressive disorder.Archives of General Psychiatry,67(11),1128–1138.

Wagner,G.,Koch,K.,Schachtzabel,C.,Peikert,G.,Schultz,C. C.,Reichenbach,J. R.,… Schlösser,R. G. (2013).Self-referential processing influences functional activation during cognitive control: An fMRI study.Social Cognitive and Affective Neuroscience,8(7),828–837.

Walter,H.,Wolf,R. C.,Spitzer,M.,& Vasic,N. (2007).Increased left prefrontal activation in patients with unipolar depression: An event-related,parametric,performance-controlled fMRI study.Journal of Affective Disorders,101(1-3),175–185.

Wang,X. L.,Du,M. Y.,Chen,T. L.,Chen,Z. Q.,Huang,X.Q.,Luo,Y.,… Gong. Q. Y. (2015). Neural correlates during working memory processing in major depressive disorder.Progress in N euro-psychopharmacology &Biological Psychiatry,56,101–108.

Whalen,P. J.,Rauch,S. L.,Etcoff,N. L.,McInerney,S. C.,Lee,M. B.,& Jenike,M. A. (1998). Masked presentations of emotional facial expressions modulate amygdala activity without explicit knowledge.Journal of Neuroscience,18(1),411–418.

Wisco,B. E. (2009). Depressive cognition: Self-reference and depth of processing.Clinical Psycho logy R eview,29(4),382–392.

Wittekind,C. E.,Terfehr,K.,Otte,C.,Jelinek,L.,Hinkelmann,K.,& Moritz,S. (2014). Mood-congruent memory in depression – The influence of personal relevance and emotional context.Psychiatry R esearch,215(3),606–613.

Yang,W. H.,Zhu,X. Z.,Wang,X.,Wu,D. X.,& Yao,S. Q.(2011). Time course of affective processing bias in major depression: An ERP study.Neuroscience Letters,487(3),372–377.

Yao,S. Q.,Liu,M. F.,Liu,J. P.,Hu,Z. J.,Yi,J. Y.,&Huang,R. Z. (2010). Inhibition dysfunction in depression:Event-related potentials during negative affective priming.Psychiatry Research,182(2),172–179.

Yoon,K. L.,Joormann,J.,& Gotlib,I. H. (2009). Judging the intensity of facial expressions of emotion:Depression-related biases in the processing of positive affect.Journal of Abnormal Psychology,118(1),223–228.

Yoon,K. L.,LeMoult,J.,& Joormann,J. (2014). Updating emotional content in working memory: A depression-specific deficit?Journal of Behavior Therapy and E xperimental Psychiatry,45(3),368–374.

Zhong,M. T.,Zhu,X. Z.,Yi,J. Y.,Yao,S. Q.,& Atchley,R.A. (2011). Do the early attentional components of ERPs reflect attentional bias in depression? It depends on the stimulus presentation time.Clinical N europhysiology,122(7),1371–1381.