Correlation of Global DNA Methylation with Symptom Severity in Drug-Naïve Bipolar Disorder Patients: A Cross-sectional Study

Abstract

health problem in India. Global Deoxyribonucleic Acid (DNA) methylation studies could provide a significant clues toward the early identification of high-risk individuals. Aim: To estimate the levels of global DNA methylation in drugnaïve bipolar disorder patients and healthy controls and to correlate the global DNA methylation levels with the severity of the disease. Materials and Methods: A cross-sectional study was conducted in the Department of Psychiatry at SCB Medical College, Cuttack, Odisha, India, from January 2019 to March 2020. A total of 50 bipolar disorder patients and 50 age-matched healthy adult controls were recruited from the Outpatient Departments (OPD) of the hospital, and the severity of bipolar disorder was assessed using Young's Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale (HAM-D). DNA methylation levels were estimated from serum samples of the subjects using a methylated DNA quantification kit. The data was analysed using Statistical Package for Social Sciences (SPSS) version 25.0. The Kruskal-Wallis test was used to compare the DNA methylation scores, and the Pearson’s correlation test was used to correlate DNA methylation levels with disease severity. A p-value <0.05 was considered significant. Results: The mean age of the study participants was 34.44±12.45 years. A total of 100 subjects were included in the study, with 50 being bipolar disorder patients and the remaining 50 in the control group. Bipolar cases, particularly depression, had higher levels of DNA methylation than controls (p=0.0001). On correlation analysis, patients with Bipolar Depression (BD) had a significant correlation with DNA methylation (p-value <0.001) compared to patients with mania and controls. Conclusion: Bipolar patients, especially those with BD, exhibit higher levels of global DNA methylation in genes compared to healthy control groups. Global DNA methylation can serve as an important early disease marker for bipolar patients, aiding in prevention and early detection efforts.