<p>Neuropsychiatric disorders (NPDs) affect more than 125&#xa0;million individuals globally. Major depressive disorder (MDD), bipolar disorder (BPD) and schizophrenia remain as the most addressed NPDs. Several inflammatory molecules such as IL-1β, IL-6, TNF-α, etc. are differentially expressed in different diseases, yet a common distinguishing biomarker is lacking. Therefore, it is potentially important to ascertain a common marker among three diseases. RNA sequencing (RNA-seq) data of three diseases were downloaded from Gene Expression Omnibus (GEO), and differentially expressed genes (DEGs) were obtained using <i>edgeR</i> package, unveiling that majority of the genes which were downregulated in MDD are being upregulated in the other two disorders. Gene ontology (GO) enrichment of 332 common genes among DEG list from three disorders were performed. Inflammation processes and immune-related genes were discovered using biological process enrichment, out of which five genes were shown to have high diagnostic efficiency value, indicating the capability of becoming a biomarker for the said disease. The genes were collectively termed as gene of interest (GOI). Immune cell deconvolution was performed to view the abundance of immune cell types in the concerned tissues. Eventually, protein-protein interaction (PPI) network, transcription factor (TF) network and miRNA network were prepared to understand the interactome within the genes. This study opens an insight into the field of psychiatric disorder treatment by providing five newer inflammatory biomarkers in addition to previously established markers, thereby, paving the way for advanced structural linking of the candidate markers to the concerned disease models using patient-derived cells.</p>