 This study examined the relationship between circulating brain-derived neurotrophic factor, BDNF, various inflammation markers and clinical characteristics in patients with major depressive disorder, MDD. The results showed that increased levels of platelet-poor plasma BDNF, PPPBDNF were associated with elevated inflammatory markers in patients with specific episode characteristics while decreased levels of platelet BDNF, PLTBDNF were related to a diagnosis of long-term depression. These findings suggest that PPPBDNF and PLTBDNF may be used as biomarkers to distinguish between MDD subtypes. Additionally, these results indicate that peripheral biomarker profiles could provide valuable information about the severity of depression and its course over time. This article was authored by Valentina Fulaski, Lionella Paligo, Donatella Marisidi, and others.