Predictive inflammatory biomarkers for change in suicidal ideation in major depressive disorder and panic disorder: A 12-week follow-up study

Previous studies have investigated the role of inflammatory markers in suicidality of patients with major depressive disorder (MDD) or panic disorder (PD). However, few studies have investigated associations between serum inflammatory cytokine levels and suicidality. We hypothesized that MDD and PD status might be significantly associated with serum inflammatory cytokines and that we could predict levels of improvement in suicide ideation intensity using serum inflammatory biomarkers in patients with MDD and PD. For this study, 41 patients with MDD, 52 patients with PD, and 59 healthy control (HC) subjects were enrolled. Psychological measurements and serum inflammatory markers such as interleukin (IL)-6, -10, interferon (IFN)-gamma, tumor necrosis factor (TNE)-alpha, and C reactive protein (CRP) were examined. A total of five visits were completed during 12 weeks. After controlling for confounding factors, log-transformed IL-6 (ln_IL-6) at baseline (MDD: 0.297 +/- 0.626; PD: 0.342 +/- 0.723; HC: -0.121 +/- 0.858; p = 0.007, >0.0017, 0.05/30) and mean ln_IL-6 (MDD: 0.395 +/- 0.550, PD: 0.249 +/- 0.544, HC: -0.139 +/- 0.622, p = 0.002, >0.0017, 0.05/30) levels were trends towards significantly higher in patients with MDD and PD than in HC. In MDD patients, a higher level of basal ln_TNF-alpha was a significant predictor of Delta SSI (changes in SSI scores between baseline and week 12) even after controlling for changes of depression symptoms and baseline SSI scores (standardized beta = 0.541, p = 0.002 < 0.0028, 0.05/18). In conclusion, we could predict Delta SSI using baseline inflammatory biomarkers for patients with MDD.

Automated summary

This study investigated the associations between serum inflammatory cytokine levels and suicidality in patients with major depressive disorder (MDD) and panic disorder (PD). Results suggest that MDD and PD patients may have significantly higher levels of inflammatory markers compared to healthy controls. Furthermore, higher baseline levels of TNF-alpha in MDD patients were found to be a significant predictor of changes in suicide ideation intensity.