Objective: To assess the metabolic alterations of the thalamus in subjects with schizophrenia compared to healthy subjects and to investigate whether specific schizophrenic symptoms are associated with metabolic alterations measured by 1 H MRS. Methods: This is a case-control study including patients with schizophrenia diagnosed using the Diagnostic and Statistical Manual of Mental Disorders -Fourth Edition, DMS-IV and the Operational Criteria Checklist for Psychotic Illness (OPCRIT). Proton

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... netic resonance spectroscopy ( 1 H MRS) was used to assess metabolite concentrations (N-acetylaspartate, choline, creatinine, myoionositol and lactacte) in the left and right thalamus of 13 patients with schizophrenia and 13 healthy controls. Results: In this study, concentrations of specific metabolites in the thalamus, determined by 1 H MRS, were similar for individuals with schizophrenia and controls. It was observed that cases with family history of schizophrenia and disorganized speech demonstrated a reduction in the ratio of the metabolites NAA /Cho in the thalamic nuclei on the right side. However, those with organized delusions, hallucinations and non-affective auditory hallucinations had an increase of metabolites on the right side compared to the left thalamus. Decreased thalamic metabolic activity in patients with positive symptoms was observed in contrast with those who had well-organized delusions and auditory non-affective hallucinations, core symptoms of schizophrenia. Conclusion: A lateralized thalamic involvement was verified, suggesting that organic and genetic factors compromise the right thalamus and that the disorganization associated with delusions and hallucinations compromises the left thalamic nuclei. Further studies to investigate the correlation between symptoms and thalamic dysfunction are warranted. (Rev Neuropsiquiatr 2011;74:183-190).