Comparison of brain metabolisms of patients with bipolar disorder with and without a history of lifetime psychotic symptoms with 18F-FDG PET/CT

Objective: Bipolar disorder is a mood disorder with attacks and often accompanied by psychotic symptoms. The accompanying psychotic symptoms worsen the functionality, prognosis, clinical profile, and increase hospitalization and use of antipsychotics. In neuroimaging studies in bipolar disorder, structural and metabolic differences were observed in various brain regions. In this study, we compared the brain metabolism of bipolar patients with and without a history of lifetime psychotic symptoms with 18F-FDG PET/CT. Method: Twenty-six bipolar disorder patients with a history of lifetime psychotic symptoms and twenty-six bipolar disorder patients without a history of lifetime psychotic symptoms were included in the study. Participants were scanned with 18F-FDG PET/CT. Twenty-six healthy controls who were retrospectively screened and met the exclusion and inclusion criteria were included in the study. Regional brain glucose metabolisms recorded as uptake ratio and z score were compared. Results: We found that glucose metabolism in the fusiform gyrus and insula was statistically lower in the group with a history of lifetime psychotic symptoms compared to the other groups (p<0,05). In bipolar patients, we determined that the uptake ratio and z score values of the right lateral prefrontal cortex, right medial prefrontal cortex, right and left sensorimotor cortex, right anterior cingulate cortex, right and left posterior cingulate cortex, right and left precuneus, left inferior parietal cortex, right and left lateral occipital cortex, right and left lateral temporal cortex, right and left mesial temporal cortex areas were statistically lower than the healthy control group (p<0,05). Conclusions: To the best of our knowledge, this study is one of the rare studies examining the etiopathogenesis of psychotic symptomatology with FDG PET / CT. The data of our study show that the fusiform gyrus and insula may be biomarkers for psychotic symptoms, and the aforementioned brain regions may be responsible for the etiopathogenesis of bipolar disorder. Further studies are needed in the future to understand this issue better.