The relationship between inflammatory response and disease severity and gender in the manic and remission phases of bipolar disorder

Purpose: This study aimed to compare inflammatory marker levels during manic episodes and early remission in patients with bipolar disorder (BD), in light of increasing evidence linking mood episodes to alterations in systemic inflammation. Furthermore, it sought to examine the association between inflammatory markers and illness severity, as well as to explore potential gender-related differences in these inflammatory responses. Materials and Methods: This retrospective clinical study included 61 patients diagnosed with BD manic episodes and treated and 64 healthy control subjects. Hemogram values, C-reactive protein (CRP), albumin levels and Young Mania Rating Scale (YMRS) scores were measured within 24 hours of admission and at discharge. Results: In patients with BD experiencing a manic episode, CRP (0.96 ± 2.02 mg/L), CRP/albumin ratio (CAR) (0.24 ± 0.534), neutrophil count (5.81 ± 3.42 × 10³/µL), and mean platelet volume (MPV) (8.11 ± 1.302 fL) levels were higher compared to healthy controls [control group: CRP (0.21 ± 0.34 mg/L), CAR (0.046 ± 0.075), neutrophil count (4.22 ± 1.26 × 10³/µL), MPV (9.78 ± 1.97 fL)]. Albumin levels in the patient group (4.19 ± 0.43 g/dL) were lower than those in the controls (4.65 ± 0.23 g/dL). The monocyte level and systemic immune response index values significantly increased after treatment in female but not in male patients. A negative correlation was identified between the YMRS scores and inflammatory markers in females for albumin and monocytes, while in males, a negative correlation was identified for CRP and CAR. Conclusion: These findings highlight the role of systemic inflammation in BD and suggest gender-specific differences in disorder characteristics and treatment responses, warranting further investigation.