Purpose: The purpose of this study was to identify the associations of chronic physical disease between patients with severe mental illness and the general population of South Korea. Methods: This study was conducted with National Health Insurance Corporation (NHIC) data from 2014 to 2019. A total of 842,459 people were diagnosed with severe mental illness (SMI) in this period, and the same number of controls were established by matching by sex and age. A descriptive analysis was conducted on the sociodemographic characteristics of patients with SMI. Conditional logistic regression analysis was performed to identify the associations between comorbid physical disease in patients with SMI and those of the general population. SAS Enterprise Guide 7.1 (SAS, Inc, Cary, NC) were used to perform all statistical tests. Result: The analysis revealed significant differences in medical insurance, income level, and Charlson Comorbidity Index (CCI) weighted by chronic physical disease, between patients with severe mental illness and the general population. Conditional logistic regression analysis between the two groups also revealed significant differences in all nine chronic physical diseases. Conclusions: The study found that people with severe mental illness had more chronic comorbid physical diseases than the general population. Therefore, people with severe mental illness have a reduced quality of life and a higher risk of excess mortality.

BackgroundSeveral studies have produced a large body of evidence for white matter abnormalities related to schizophrenia. The literature has yet to achieve a state of consistency and reproducibility, and reported low integrity of white matter tracts vary between studies. Whole brain image study with large sample size is needed to address this issue. We investigated white matter integrity in connections between regions of interests (ROI) in the same hemisphere in patients with schizophrenia and healthy controls with public neuroimaging data from SchizConnect (http://schizconnect.org).MethodsA final data set was consisted of 129 healthy controls and 122 schizophrenia patients. For each diffusion weighted image (DWI), a two-tensor full-brain tractography was performed, and DWI images were parcellated by processing and registering the T1 images with FreeSurfer and the Advanced Normalization Tools. We extracted a total of 36 tracts in the both hemisphere connecting ROIs in the same hemisphere with white matter query language. We compared means of diffusion measures between patients and controls, and evaluated correlations with Letter-number sequencing (LNS) test, Vocabulary test, letter fluency test, category fluency test, and trails A of the Trail Making Test (TMT). The Benjamini-Hochberg procedure with false discovery rate (FDR) of 0.05 was used to correct for multiple comparisons.ResultsWe found a significant RD and TR increase of the left thalamo-occipital tracts and the right uncinate fascicle (UF), and a significant RD increase of the right middle longitudinal fascicle (MDLF), and the right superior longitudinal fascicle (SLF) ii in schizophrenia. There were correlations between the TR in the left thalamo-occipital tracts and letter fluency test, and the RD in the right SLF ii and LNS test, which did not survive after correction for multiple comparisons.DiscussionThese results indicate widespread abnormalities of white matter fiber tracts in schizophrenia, contributing to the pathophysiology of schizophrenia.