Can complete blood count parameters be a good marker for substance use disorder?

Objective: Inflamatory processes play an important role in the etiology of psychiatric disorders. The aim of this study was to evaluate inflammatory complete blood count (CBC) parameters in substance use disorder (SUD). Methods: The study included 90 patients with SUD and 90 healthy controls (HC). The Student t-test was used to compare CBC parameters between the groups. The Kruskal–Wallis test was used to compare the data on the basis of substance types. Results: Leukocyte, lymphocyte, and monocyte levels were higher in SUD group than HC. Leukocyte and neutrophil levels of patients with opioid use disorder (OUD) were higher than HC. Platelet levels and neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and systemic immune inflammation index values were higher in patients with OUD than in patients with non-opioid substance use disorder (nOUD). Moreover, lymphocyte and monocyte levels were higher in patients with nOUD than in HC. Monocyte levels were increased in patients with cannabinoid use disorder compared to HC. Conclusion: The results suggested that inflammatory CBC parameters play an important role in the etiology of SUD according to type of substance. However, there is not enough data for supporting the clinical use of these parameters.