Intrinsic Motivation In Schizophrenia: Association With Theory Of Mind

Objective Intrinsic motivation is human innate tendency of pursuing of novelty andchallenge, developing and exercising oneself, having courage to explore and study. Ithas highly autonomous, representing the prototype of self-determination. Intrinsicmotivation plays an important role in individual psychological function, and theory ofmind is the basis of infering others mental states. Schizophrenia is a degenerative braindisease with a broad range of psychological activitiy damage, which brings about widedamage of advanced cognitive function. The theory of mind deficite of schizophreniapatients has been widely recognized. The relationship of schizophrenia’s intrinsicmotivation defects and negative symtoms has long been concerned. The intrinsicmotivation defects may affect schizophrenia’s social function rehabition. But there isstill no evidence indicates there is a connection between change of intrinsic motivationwith the theory of mind of schizophrenia. We assume the theory of mind deficite ofschizophrenia patients assocaited with the damage intrinsic motivation, and thecorrealtion may be independent of psychotic symptom.This study attempts to assess the intrinsic motivation level of schizophrenic patients,and explores the relationship between intrinsic motivation and the theory of mind ofschizophrenia patients.Methods70schizophrenia patients without treatment and60age, gender and years ofeducation-matched healthy control subjects were meatured with Intrinsic MotivationInventory for Schizophrenia Research (IMI-SR) and Theory-of-MindPicture-Sequencing Task (ToM-PST). Results Compared with healthy subjects, schizophrenic patients showed significantlydecreased IMI-SR total score (97.77±27.31vs88.43±22.42, P<0.01) and subscores ofinterest (32.03±8.29vs29.11±8.31, P<0.05) and choice (35.33±9.85vs29.71±8.82,P<0.01). Schizophrenic patients also had significantly less total score (36.59±11.85vs57.17±2.08, P<0.01) and subscores of ToM-PST compared to normal controls (allP<0.01). Correlation analysis showed a negative correlation between IMI-SR total scoreand PANSS total score(r=-0.255, P<0.05) and the subscores of negative symptoms(r=-0.361, P<0.01) and positive symptoms (r=-0.298, P<0.05). There was significantlypositive correlation between IMI-SR total score (r=0.345, P<0.01) and its subscores ofthe understanding of first order belief (r=0.296, P<0.05), the understanding of first orderfalse belief (r=0.243, P<0.05), first order belief total points(r=0.311, P<0.01), theunderstanding of second order false belief(r=0.254, P<0.05), second order belief totalpoints(r=0.284, P<0.05), the understanding of intended deception(r=0.286, P<0.05) inschizophrenic patients. After controlling for the PANSS total score, the correlationbetween IMI-SR total score and ToM-PST total score and its subscores of theunderstanding of first order belief, first order belief total score, the understanding ofsecond order belief, second order belief total score, the understanding of intendeddeception was remain significant.Conclusion Schizophrenia patients had impairments of intrinsic motivation and theoryof mind, and intrinsic motivation deficit may shared a common pathophysiological basewith the impairment of theory of mind.