Possible association between social cognition and metabolic dysfunctions in Bipolar Disorder and Schizophrenia: Preliminary results

Background: Social cognition (SC) and Theory of Mind (ToM) are compromised in patients with Schizophrenia (SKZ) and Bipolar Disorder (BD) and an increased frequency of metabolic abnormalities is reported in both disorders. Obesity seems associated with cognitive impairments The aim of our study is thus to assess the relationship between obesity and ToM in SKZ and BD. Methods: 36 stabilized outpatients (18 SKZ and 18 BD) were recruited and completed Reading the Mind in the Eyes Test, Italian version and Faux Pas Recognition Test, adult version. BMI was calculated from self-reported height and weight. Two different Generalized Linear Models were created including performance in Eyes test and in Faux Pas test as outcomes and BMI as covariate. Results: After stratifying for sex, we found a significant relationship between BMI and Faux Pas performance for male patients (p = 0.017), without significant interactions between sex and diagnosis. These results suggest a BMI effect on both affective and cognitive ToM in male patients. Limitations: Major confounders need to be considered: the greater number of subjects with SKZ in male subsample, a possible influence of neurocognitive performance, small sample size and self-reported BMI. Conclusions: There could be a relationship between ToM and metabolic dysfunctions, at least in male patients. The exact nature of this relationship has yet to be determined; an interesting theoretical framework is based on a combination of increased brain energy request and inefficient peripheral compensatory mechanisms, resulting in inefficient energy allocation to the brain.