Unconscious Processing Of Emotional Face Among Patients With Generalized Anxiety Disorder: An Event-related Potential Study

Objective: Generalized anxiety disorder （GAD）, also known as chronic anxiety, ischaracterized by excessive worry and tension on the day-to-day events or activities.Although the pathogenesis of generalized anxiety disorder has not yet been achieved theconsistency of conclusions, most studies generally suggest that abnormal processing ofemotional information may be one of the important features of GAD.Unconscious processing is characterized by information processing with no or littleawareness, without taking up the attentional resources and without awareness to initiate.Given that GAD patients show nervous and excessive worry lacking of clear object orfixed content, it is speculated that the abnormal processing of emotional information islikely to occur on the unconscious level. Studies have shown that information ofemotional face is more easier to be processed by unconscious processing. Event-relatedpotentials （ERP） can be used to accurate to the millisecond and to reflect the dynamicprocess of cognitive processing, so it is the best technical means of studyingunconscious processing. The purpose of the this study is to explore the unconsciousprocessing of emotional face in GAD patients by using of ERP and to further analyzewhether the different emotional contents are specific to generalized anxiety disorder.Methods: In this study, subliminal affective priming task and a64channelNeuroscan electroencephalogram were used to record the event-related potentials. Afteroff-line analysis, the P1and P3a elicited by different emotional faces were measured inthe frontal, parietal, occipital electrodes and the central electrodes. Mean amplitudes andpeak latency were subjected to repeated measures analysis （Repeated measureANOVA）.Results:1.There was a significant group difference in both groups(F_1,28=15.296, p < 0.05), ratings for fearful trials were higher in GAD patients（4.521±0.221）than that incontrols（4.159±0.282）.2.The amplitudes of the P1and P3a were significantly higher in GAD patients thanthat in controls（p <0.01）. Further analysis revealed that two types of emotional faceshad statistical difference only in GAD patients（p <0.05）, showing a greater P1amplitude elicited by fearful face （12.634±0.057） and a greater P3a amplitude elicitedby happy face （10.077±0.032）.3.There was a significant main effect between the group for the peak latency ofP1(F_1,28=3.598, p <0.01), and the peak latency in GAD patients（100.579±0.46）was significantly shorter than the peak latency in normal controls（139.575±0.46）.4.The amplitudes of the two ERP components were significantly higher at righthemisphere than that at left hemisphere（p <0.01）.Conclusion:1.GAD patients have abnormal unconscious processing of emotional faces.2.There is a specificity for the abnormal unconscious processing of emotional facesin GAD patients, showing enhanced unconscious processing of negative emotions.3.Automatic processing of emotional information is right-lateralized in GADpatients.