Comparison of serum BDNF, IL-1β, IL-6, TNF-α, CRP and leucocyte levels in unipolar mania and bipolar disorder.

Objective: Unipolar mania is not included in the diagnostic and statistical manual of mental disorders-5 (DSM-5) as a separate diagnosis, although it is defined by widely accepted diagnostic criteria. The aim of this study was to investigate the differences between unipolar mania and bipolar disorder in terms of clinical and inflammatory parameters.

Methods: The data of 495 hospitalised patients with bipolar disorder diagnoses were analysed retrospectively. Forty met the diagnostic criteria for unipolar mania. Two patients refused to participate in the study. Thirty-eight unipolar mania patients and 42 randomly selected patients with bipolar disorder diagnosis were included in the study. The two groups were compared in terms of sociodemographic, clinical characteristics, serum brain-derived neurotrophic factor, C-reactive protein (CRP), leucocyte and cytokine levels.

Results: A total of 40 (8.08%) of 495 patients diagnosed with bipolar disorder met the unipolar mania diagnostic criteria. The number of manic episodes and the number of hospitalisations were statistically higher in the unipolar mania group than in the bipolar disorder group. Among all the manic symptoms, the incidence of symptoms such as euphoria, increased sexual interest, grandiosity and delusions were found to be statistically higher in the unipolar mania group. Interleukin (IL)-6 and CRP levels were significantly higher in the unipolar mania group than in the bipolar disorder group.

Conclusion: Unipolar mania differs from bipolar disorder in terms of clinical features and serum IL-6 and CRP levels.