Inflammatory protein markers and treatment outcomes across mood and psychotic disorders: a systematic review and meta-analysis.
Chiara Possidente, Arianna Biancalani, Bernhard T Baune et al.
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In 30 seconds
This systematic review and meta-analysis examined associations between peripheral inflammatory proteins and psychopharmacological treatment outcomes in schizophrenia, bipolar disorder (BD), and major depressive disorder (MDD). The review included 105 studies, with 42 contributing to meta-analysis; evidence was weighted toward MDD, while BD was least represented. IL-6 showed no association with outcomes. Responders had a greater baseline-to-endpoint decrease in TNF-α (SMD = 0.75, 95% CI [0.14-1.35]; k = 7), and lower baseline CRP was associated with remission (OR = 1.84, 95%CI [1.33, 2.54]; k = 6).
Key findings
- IL-6, the most studied marker, was not associated with treatment outcomes.
- Responders showed a greater baseline-to-endpoint TNF-α decrease (SMD = 0.75, 95% CI [0.14-1.35]; k = 7).
- Low versus high baseline CRP was associated with remission (OR = 1.84, 95%CI [1.33, 2.54]; k = 6), although cut-offs varied.
- Baseline IL-8 was higher in non-responders with mood disorders (SMD = -0.38; 95%CI [-0.73, -0.03]; k = 6); heterogeneity was high across most analyses.
Why it matters
The findings suggest that inflammatory proteins may relate to some treatment outcomes, but their predictive value across these disorders remains limited. The evidence base is uneven, particularly for BD, and substantial heterogeneity complicates interpretation. These results caution against treating individual inflammatory markers as established cross-diagnostic predictors and highlight the need for more consistent research methods.
What to keep in mind
Evidence was substantially weighted toward MDD, BD was least represented, and heterogeneity was high across most analyses. CRP cut-off definitions varied across studies.