Erp Study On Pain Empathy In Patients With Bipolar Disorder At Different Stages

Objective: BD,or Bipolar disorder,is considered an severe mental disease.Emotion of patients with BD is extremely unstable--they will shift between depression and mania,and the period usually can not be predicted.Patients with BD have difficulties in emotion recognizing,perspective taking and self-expressing.Empathy for pain is the perception and reaction to others' painful feelings based on our own experience of pain sense,and it can decrease the mutual hurtful behaviors among human,increase cooperation and promote social harmony.Researches show that the empathy for pain of patients with BD is undermined,however,current researches view patients with BD as a whole,and few of such researches aim their empathy for pain and recognition mechanism in different clinical phases(mania,depression and remission phase).Adopting ERP(short for event-related potential)with high temporal resolution and combining classic pain empathy paradigm,this article analyzes empathy for pain and recognition mechanism of patients with BD in different clinical phases.Method:(1)Objectives: including 21 patients in mania phase,17 patients in depression phase,20 patients in remission phase and 20 healthy people for control group.Objective patients met the diagnosis criterion of BD according to International Classification of Diseases(shorten for ICD-10),and were diagnosed as BD by two chief or higher level psychiatrist.Patients scored 12 or more in Young Mania Rating Scale(shorten for YMRS),and met the diagnosis criterion of ICD-10 for mania or slight mania in the meantime,were included into patient group of mania phase;Patients scored 17 or more in 17-item Hamilton Rating Scale for Depression(shorten for HAMD-17),and met the diagnosis criterion of ICD-10 for depression in the meantime,were included into patient group of depression phase;objective patients with BD in remission phase were required to take medicine for at least four weeks,clinically diagnosed by chief or higher level psychiatrist as stable period for more than three months,scored 8 or less in HAMD-17 and 6 or less in YMRS;patients treated with electric shock treatment in the last six months,patients with history of brain injury,with other mental illnesses,or with substance dependence and patients in rapid circulation phase were excluded.Healthy people for control group were required a history of no personal or family mental illnesses,matched demographic data with patients;healthy people with unmatched demographic data,history of brain injury and color weakness or blindness were excluded.(2)Experimental materials of empathy for pain: Chinese Version of Interpersonal Reactivity Index(shorten for IRI-C)and pain empathy paradigm were adopted to explore empathy for pain of patients with BD.While the objectives were taking experiments,their brain electric waves were being recorded.Results:(1)IRI-C scores: patients with BD in mania and depression phase scored lower than healthy control group in Personal Distress,while patients in remission phase also scored lower in Personal Distress,but the differences were not significant.(2)Behavioral Results: Objectives' judgment accuracy to negatively stimulating pictures in pain judgment task was notably lower than to negatively stimulating pictures in left-right judgment task,which suggested that the reaction to negatively stimulating pictures are affected by the change of tasks.Facing negative stimulus or neutral stimulus,objectives took notably more correct reaction time in the pain judgment task than in the left-right judgment.The result of correct reaction time showed that objectives took more time to react when judging weather others are injured,suggesting that the judging process of pain recognition of individuals might be more complicated.(3)Results of Brain Electric wave: In late component P3,patients with BD in mania,depression and remission phases had no significant difference in brain electric waves induced by neutral stimulus.To healthy people in the pain judgment task,negative stimulus induced greater late component P3 brain electrical wave,however,in left-right judgment task,late component P3 brain electrical wave induced by negative stimulus and neutral stimulus showed no significant amplitude difference.Conclusion: No significant amplitude difference was found between early component N1 and late component P3 brain electric waves that induced by negative stimulus and neutral stimulus of patients with BD in mania,depression and remission phase.And those patients showed no pain effect,scored notably lower than control group in IRI-C,suggesting that their empathy for pain was damaged in trait,which remains even in remission phase.