Structural MRI of the Brain in Treatment-Resistant Schizophrenia

Background: despite a significant progress of psychopharmacology, treatment-resistant schizophrenia (TRS) remains a challenge for clinicians. The etiology and pathogenesis of TRS probably differ from schizophrenia susceptible to therapy, which underlies the non-respondence to most antipsychotics. Objective: to establish morphometric gray matter brain structural features in TRS as well as to analyze the association of these parameters with the clinical characteristics of patients. Patients and methods: 21 right-handed male patients diagnosed with paranoid schizophrenia and meeting criteria for treatment resistance and 21 matched healthy controls underwent MRI and clinical examination. T1-weighted images were processed via FreeSurfer 7.1.1. For each subject average values for the cortex thickness and area, volumes of subcortical structures, brain stem structures, and separately volumes of the amygdala nuclei and hippocampal subregions were obtained. Intergroup comparisons and correlations with clinical scales (PANSS, CDSS) and antipsychotic dosage in chlorpromazine equivalent were calculated. Results: TRS patients showed decreased gray matter thickness in frontal, temporal, parietal, occipital, cingulate and insular regions, volumes of the amygdala, hippocampus and nucleus accumbens, as well as a number of amygdala nuclei and hippocampal subregions bilaterally. The volume of the right globus pallidus, on the contrary, was increased. Conclusion: the widespread gray matter thinning in TRS confirmed the other researchs, which described resistance as a more severe form of schizophrenia that affects brain structures worse. The increase of globus pallidus volume is a surprising result, which is not yet clearly explained.