In recent years, an increasing amount of research has investigated the impact of chronic inflammation on the development and progression of both neurological and psychiatric disorders, including epilepsy, depression, schizophrenia, and bipolar disorder. Moreover, growing attention is being paid to how inflammatory processes contribute to disease mechanisms, influence symptom severity, and interact with pharmacological treatments in these conditions. Changes in the levels of inflammatory biomarkers, such as cytokines and C-reactive protein, may signal the early stages of neurological disorder development. Furthermore, specific biomarker profiles have been identified for individual diseases, and chronic treatment may affect their blood levels. Over the last two decades, significant progress in the study of inflammatory biomarkers in psychiatric disorders and epilepsy has been achieved, demonstrating an association between biomarkers with symptoms, a potential prognostic role, and possible use in personalising therapy. Furthermore, widely used methods for biomarker evaluation, such as immunoenzymatic assays and flow cytometry, remain essential tools for current research. Despite numerous indications of the importance of inflammation in psychiatry and neurology, the available studies are characterised by considerable heterogeneity in terms of both population selection and methodology. Based on the available data, inflammatory biomarkers represent a promising diagnostic and therapeutic tool for epilepsy and psychiatric disorders. Although existing studies suggest a correlation between inflammation and the symptoms of various disorders, inconsistent results highlight the need for further research to enable wider implementation of these findings in psychiatric and epilepsy practice. Advancing knowledge of inflammatory biomarkers is essential for improving treatment outcomes and promoting the development of targeted interventions.