Peripheral Physiological-Changes In Response To External Emotions And Their Transitions In Bipolar ? And ? Disorders

BackgroundBipolar disorder is a serious mental disease characterized by recurrent mania/hypomania and depression.It has two main subtypes:bipolar ? and bipolar ? disorders,which might be distinguished based on epidemiologic,genetic,and clinical features.However,there are only a few studies on their emotional reactivity to external emotional stimuli.within bipolar ? and ?,mania/hypomania and depression play different roles.Bipolar ? is defined by equally serious mania and depression,while bipolar ? is primarily defined by serious depression and hypomania in bipolar ? is far less serious than depression,but more evidence is needed in this respect.Previous studies have seldom compared bipolar ? and ? disorders,which limits our understanding on the fundamental differences between them.On the other hand,affective states can modulate emotion reactivity in human.Previous studies have been focused on emotional reactivity to external stimuli of certain emotions,and few have involved the mutual modulatory effects of emotions.This dampens our comprehensive understanding of emotional reactivity.In the present study,we compared bipolar ? and ? disorders on their emotional reactivity to further our understanding of the fundamental difference between the two subtypes;meanwhile,we looked into the mutual modulatory effects of discrete emotions.Results in these respects will not only contribute to the development of emotion regulation theories in the context of bipolar disorder but also benefit the diagnosis,therapy,and management of this and other relevant mental disorders.Hypotheses(1)Bipolar ? and ? disorders differ in their peripheral activity during resting state.(2)Bipolar ? and ? disorders react differently to positive(e.g.erotica and happiness),negative(disgust,fear,and sadness),and neutral emotional stimuli.Bipolar ? reacts more actively to positive emotions,while bipolar ? diminishes reactivity to both positive and negative stimuli.(3)Bipolar ? and ? disorders portray different features in emotional mutual modulations,and some features might be relevant to affective states of patients.Methods(1)For aim one,we invited 139 healthy volunteers,69 bipolar ? and 54 bipolar ? patients and administered the Mood Disorder Questionnaire,Hypomania Checklist-32,and the Plutchik-van Praag Depression Inventory to them to seek group differences of affective states.We then collected data of electrocardiography,galvanic skin conductance,electrooculography and electromyography from all participants on a resting state,calculated the electrocardiographic RR interval,skin conductance,eye movement speed,and root mean square of masseter electromyography to seek group differences of peripheral activity on resting state.(2)For aim two,we selected pictures and sounds that can provoke emotions such as disgust,erotica,fear,happiness,neutral and sadness to compose scenes of distinct emotions.These scenes were used as external emotional stimuli.We calculated electrocardiographic RR interval,skin conductance,eye movement speed,and root mean square of masseter electromyography in response to the emotional stimuli for the aforementioned 139 healthy volunteers,69 bipolar ? and 54 bipolar ? patients.We compared these measures to seek group differences of peripheral reactivity to different emotional stimuli and analyzed their relationship with affective states.(3)For aim three,we composed 20 emotional transitions using sadness,happiness,erotica and neutral as target emotions and disgust,erotica,fear,happiness,neutral,and sadness as background emotions.We calculated electrocardiographic RR interval,skin conductance,eye movement speed,and root mean square of masseter electromyography in response to the emotional transitions for the aforementioned 139 healthy volunteers,69 bipolar ? and 54 bipolar? patients.We compared these measures to seek group differences of peripheral reactivity to different emotional transitions,and analyzed their relationship with affective states.Results(1)Bipolar ? scored higher on depression than bipolar ? and healthy controls did,and bipolar ? higher than healthy controls did.Bipolar ? scored higher on mania than bipolar ? and healthy controls did.Both bipolar ? and ? scored higher on hypomania than healthy controls did,and bipolar ? higher than bipolar ? did.The root mean square of masseter electromyography on resting state was higher in bipolar ? than that in healthy controls.(2)The eye movement speed was higher in bipolar ? than that in healthy controls during erotica.The skin conductance was lower in bipolar ? than that in healthy controls during fear and higher in bipolar ? than that in healthy controls during disgust.(3)During fear after neutral,the RR interval was longer in bipolar ? than that in bipolar ?.During happiness after disgust,the eye movement speed was higher in bipolar ? than that in healthy controls.During sadness after disgust,the eye movement speed was higher in bipolar ?than that in bipolar ?.During disgust after neutral,the eye movement speed was higher in bipolar ? than that in healthy controls.During fear after erotica,skin conductance was higher in bipolar ? than that in healthy controls.During disgust after sadness,the root mean square of masseter electromyography was higher in bipolar ? than that in healthy controls.There are also some correlations between the mutual modulation of the emotions and affective states in bipolar? and ? disorders.Conclusions(1)Bipolar ? and ? disorders scored differently in mania/hypomania and depression.Bipolar ? showed more masseter activity than healthy controls did on resting state,implicating that bipolar ? patients suffered more stress.(2)Bipolar ? reacted more intensely than healthy controls did to external disgust stimuli.Bipolar ? portrayed less focus on erotica stimuli than healthy controls did.(3)In bipolar ?,fear enhanced the need for peace rather than that for intense positive emotions,implications of which may contribute to the therapy and management of bipolar ?.Also in bipolar ?,disgust enhanced reactivity to happiness.While the effect that sadness lowered somatic activity was diminished in bipolar I,it was enhanced in bipolar ?.The effect that sadness diminished the reactivity to disgust was impeded in bipolar ? and likewise,the effect that erotica enhanced the reactivity to fear was impeded in bipolar ?.(4)Bipolar ? and ? disorders scored differently on mania/hypomania and depression.They also portrayed different features in response to external emotional stimuli and their transitions.These findings will contribute to the development of diagnosis,therapy and management of bipolar ? and ? disorders.