Abstract
The studies in monozygotic twins both discordant and concordant for schizophrenia using sophisticated imaging methods provide an avenue towards better understanding of relative roles of genetic and environmental factors in the disease. Relatively novel and promising tools in neuropsychiatric research based on principle of magnetic resonance (MR) has yielded number of important findings in schizophrenia research during the last decade including MR relaxometry.
MR relaxometry provides insight into structural and functional tissue characteristics. T1 and T2 relaxation times reflect specific tissue parameters and they are potentially an index of brain dysfunction.
To assess relative contribution of genetic and nongenetic factors in physical and chemical changes of the brain tissue in schizophrenia, we examined T1 and T2 relaxation times by means of MR relaxometry in MZ twins discordant and concordant for schizophrenia. The discordant group involved in the study consisted of the twin pairs with no familial loading of a major psychiatric illness in contrast to concordant group that exhibited increased familial loading of schizophrenia and schizophrenia-spectrum disorder.
Because of the possibility that the discordant twin group from our sample is more likely to contain nongenetic cases of the illness, the comparison with the concordant twin group might highlight possible differences in metabolic changes between sporadic and genetically determined cases. Patients with schizophrenia (concordant plus affected discordant) showed significant prolongation (p < 0.0025, corrected) in T1 relaxation times in globus pallidus bilaterally, compared to healthy control twin group. : As all patients were receiving antipsychotic treatment it is yet to be determined if the observed prolonged T1 values are the result of antipsychotic medication or some other aspect of brain patophysiology characteristic of schizophrenia