Serum thiobarbituric acid reactive substances in bipolar disorder during mania and schizophrenia: a biomarker with possible diagnostic implications

  • Dr Brisa Fernandes, Bipolar Disorder Program and Laboratory of Molecular Psychiatry, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Matheus Pasquali, Universidade Federal do Rio Grande do Sul, Brazil, and INCT for Translational Medicine, Brazil
  • Rafael Bortolin, Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Brazil, and INCT for Translational Medicine, Brazil, Brazil
  • Bianca Aguiar, Bipolar Disorder Program and Laboratory of Molecular Psychiatry, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil
  • Bianca Pfaffenseller, Hospital de Clínicas de Porto Alegre, Brazil
  • Dr Jose Moreira, Universidade Federal do Rio Grande do Sul, and INCT for Translational Medicine, Brazil
  • Dr Flavio Kapczinski, Hospital de Clínicas de Porto Alegre, Brazil
  • Dr Clarissa Gama, Hospital de Clínicas de Porto Alegre, Brazil, and INCT for Tra, Brazil

Introduction: Despite established clinical criteria for manic episodes, the differential diagnosis of Bipolar Disorder (BD) during acute mania and Schizophrenia (SZ) remains a clinical challenge. BD is a disorder that affects oxidative stress, particularly Thiobarbituric Acid Reactive Substances (TBARS). This study was conceived to examine the properties of serum TBARS as a biomarker of diagnosis during acute mania.
Methods: We conducted an exploratory study with 55 patients with SZ, 20 patients with BD in a current manic episode and 80 controls. Serum TBARS levels were expressed as nmol/mg protein. Optimal sensitivity and specificity of serum TBARS for the diagnosis of BD were determined by the receiver operating characteristic (ROC) curve analysis.
Results: The sample had an age of 40.09 ± 11.39 years (mean ± SD). Eighty-two of the 155 subjects (52.90%) were male. Serum TBARS levels in patients with SZ were increased when compared to patients with mania and to healthy subjects; manic patients had higher TBARS than controls. ROC curve analysis was used to explore discriminatory values of TBARS. The area under the curve of the ROC analysis in mania vs. SZ was 0.84 (ranged from 0.75 to 0.92). A proposed ‘‘best” cutoff of 2.19 resulted in 80% sensitivity and 78% specificity.
Conclusions: Our results suggest that increased serum TBARS levels in BD may play a role as a diagnostic biomarker in the clinical setting to discriminate mania from SZ. A naturalistic study would be desirable as a natural follow-up of the present study to confirm our results.