Pharmacological therapy in mental disorders is usually effective in 60–70%, the treatment reaction is worsening with the disease progression, and proper medication and early treatment regimen choice is crucial. Research showed that specific brain changes (structural and functional) are present in depressed patients. These abnormalities are probably linked to neurodegeneration. There is also an evidence that inflammation contributes to the depression pathophysiology, and both these processes – neurodegeneration and inflammation are related.

Novel biological markers allow us to better understand the individual mechanisms of treatment response in depression. Recently, several biological measures have been proposed, amongst them – neuropsychological dysfunction, decreased GABA level in proton magnetic resonance spectroscopy (¹H MRS), body weight, genetic factors and peripheral inflammatory markers. Latest research found that brain changes assessed with neuroimaging methods (including ¹H MRS, e.g. glutamatergic system abnormalities), correlate with peripheral inflammatory markers. Furthermore, both these factors taken together may serve as one integrated treatment prediction marker in depressed patients.