title: Association between age of disease-onset, cognitive performance and cortical thickness in bipolar disorders.
abstract: OBJECTIVE
  Neuroimaging studies in patients with bipolar disorder (BD) have indicated a number of structural brain changes, including reduced cortical thickness. However, the effects of the course of illness, clinical and cognitive variables on cortical thickness in BD patients have not yet been evaluated.
  
  
  METHODS
  A total of 67 individuals (32 patients with euthymic BD and 35 healthy and age-matched controls) underwent 3D-anatomical magnetic resonance imaging (MRI). Whole-brain cortical thickness and group differences were assessed using the Freesurfer software. Course of disease variables, clinical and cognitive parameters were correlated with cortical thickness measures.
  
  
  RESULTS
  We found reduced cortical thickness in BD patients compared with controls in the frontal and temporal lobes and in several limbic areas. We also report significant associations between cortical thickness and age of disease-onset, speed of cognitive processing, executive function and depression severity in BD patients.
  
  
  CONCLUSIONS
  Cortical thickness reduction across frontal and limbic areas is a structural correlate of affective symptom severity and cognitive impairments in BD as well of age of disease-onset. We may assume that frontal lobe structural abnormalities are present in bipolar disorder, and might lead to dysfunctional cognitive functioning. The causality and functional relevance beyond mere correlation, however, is yet to be established. Our findings encourage further longitudinal studies in BD patients and in healthy at-risk subjects in order to discern the temporal order and development of morphological changes and clinical symptoms.
authors.affiliation: Laboratory of Neurophysiology and Neuroimaging, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University, Frankfurt/Main, Germany. Electronic address: Viola.Oertel@kgu.de.
authors.forename: Viola
authors.initials: V
authors.lastname: Oertel-Knöchel
authors.affiliation: Laboratory of Neurophysiology and Neuroimaging, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University, Frankfurt/Main, Germany.
authors.forename: Johanna
authors.initials: J
authors.lastname: Reuter
authors.affiliation: Laboratory of Neurophysiology and Neuroimaging, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University, Frankfurt/Main, Germany; Brain Imaging Center (BIC), Goethe-University, Frankfurt/Main, Germany.
authors.forename: Britta
authors.initials: B
authors.lastname: Reinke
authors.affiliation: Laboratory of Neurophysiology and Neuroimaging, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University, Frankfurt/Main, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Marbach
authors.affiliation: Laboratory of Neurophysiology and Neuroimaging, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University, Frankfurt/Main, Germany.
authors.forename: Richard
authors.initials: R
authors.lastname: Feddern
authors.affiliation: Center for Alzheimer׳s Disease and Related Disorders, Universidade Federal do Rio de Janeiro, Brazil.
authors.forename: Gilberto
authors.initials: G
authors.lastname: Alves
authors.affiliation: Laboratory of Neurophysiology and Neuroimaging, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University, Frankfurt/Main, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Prvulovic
authors.affiliation: School of Psychology, Cardiff University, United Kingdom; MRC Centre for Neuropsychiatric Genetics & Genomics, Institute of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, United Kingdom.
authors.forename: David E J
authors.initials: DE
authors.lastname: Linden
authors.affiliation: Laboratory of Neurophysiology and Neuroimaging, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe University, Frankfurt/Main, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Knöchel
mesh_terms: D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D001714:Bipolar Disorder / Q000473:pathology* / Q000523:psychology*; D003071:Cognition; D060825:Cognitive Dysfunction / Q000523:psychology; D003866:Depressive Disorder / Q000150:complications; D056344:Executive Function; D005260:Female; D005625:Frontal Lobe / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008032:Limbic System / Q000473:pathology; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D013702:Temporal Lobe / Q000473:pathology
keywords: Bipolar; Cognitive functioning; Cortical thickness; MRI