Metabolomics research in schizophrenia has revealed consistent alterations across multiple biochemical domains, including energy metabolism, lipid composition, amino acid pathways, and oxidative stress regulation. The most reproducible findings include the dysregulation of the tryptophan–kynurenine pathway, disturbances in arginine/nitric oxide metabolism, alterations in phospholipid and sphingolipid profiles, reduced glutathione (GSH) in the brain, and elevated lactate levels, suggesting mitochondrial dysfunction. Antipsychotic treatment itself modifies a wide range of metabolites, complicating biomarker discovery. Although no single biomarker has yet achieved clinical utility, systematic reviews and Mendelian randomization studies provide evidence for validated biomarker panels and potential causal links between peripheral metabolite signatures and schizophrenia risk. The aim of this study is to characterize metabolic changes in patients diagnosed with schizophrenia, where each group received different non-invasive therapeutic methods and was compared to patients continuing standard pharmacotherapy without modification. The study results show that schizophrenia is associated with systemic metabolic disturbances affecting energy, amino acid, lipid, and redox pathways. Further development of research in this area requires comprehensive and long-term studies integrated with modern imaging and analytical techniques.