Characterization of brain morphology in patients with
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AbstractSchizophrenia is one of the most severe and disabling mental illnesses. In spite of continuous development of treatment modalities, most patients still suffer from chronic symptoms and functional decline. The precise etiology and pathological mechanisms for the disease are not known. The development of methods for high-resolution imaging using MRI has offered new opportunities for the investigation of the brain in vivo.
The aim of the present thesis was to find and characterize structural brain abnormalities in schizophrenia using magnetic resonance imaging (MRI) methods. In separate studies differences in cortical thickness and brain tissue volumes between patients and healthy subjects, the putative effects of alcohol consumption and antipsychotic medication, and the relationships between symptom severity and brain volumes were investigated. Evidence for subgroups of patients based on cortical thickness measurements was also sought.
During the period between 1999 and 2003 a total of 96 patients with schizophrenia and 107 healthy subjects were recruited at the Karolinska Institutet in Stockholm, Sweden. This thesis is based on data from clinical and MRI investigations of these patients.
The results demonstrated that compared to healthy subjects, patients with schizophrenia have thinner cortex and smaller brain tissue volumes in prefrontal and temporal regions. The differences could not be attributed to consumption of alcohol or antipsychotic medication. Severity of positive symptoms was related to smaller brain tissue volumes, while severity of negative symptoms was related to larger brain tissue volumes. No evidence was found for subgroups of patients based on cortical thickness measurements.
The findings highlight that the brain is structurally different in patients with schizophrenia than in healthy subjects. Further investigation of the brain abnormalities may guide the search for efficient treatment options for the patients.
List of studies included in thesis
Study I Ragnar Nesvåg, Arnoldo Frigessi, Erik G. Jönsson, Ingrid Agartz. Effects of alcohol consumption and antipsychotic medication on brain morphology in schizophrenia. Schizophrenia Research 2007; 90:52-61
Study II Ragnar Nesvåg, Glenn Lawyer, Katarina Varnäs, Anders M. Fjell, Kristine B. Walhovd, Arnoldo Frigessi, Erik G. Jönsson, Ingrid Agartz. Regional thinning of the cerebral cortex in schizophrenia: Effects of diagnosis, age and antipsychotic medication. Schizophrenia Research 2008; 98:16-28
Study III Ragnar Nesvåg, Erik G. Jönsson, Peter Sætre, Glenn Lawyer, Ingrid Agartz. The relationship between symptom severity and regional cortical and grey matter volumes in schizophrenia. Under revision for resubmission.
Study IV Glenn Lawyer, Ragnar Nesvåg, Katarina Varnäs, Ingrid Agartz. Investigating possible subtypes of schizophrenia patients and controls as defined by brain cortical thickness. Psychiatry Research - Neuroimaging in press.