title: Longitudinal study examining abnormal white matter integrity using a tract-specific analysis in individuals with a high risk for psychosis.
abstract: OBJECTIVE
  Although volume reductions in the grey matter have been previously observed in individuals with an at-risk mental state (ARMS) for psychosis, the features of white matter integrity and their correlation with psychiatric symptoms remain unclear.
  
  
  METHODS
  Forty-six ARMS subjects were examined using magnetic resonance imaging (MRI) to acquire diffusion tensor imaging (DTI); the subjects were also evaluated using the Scale of Prodromal Symptoms at baseline and at 52 weeks. Sixteen healthy controls also underwent MRI scanning. The DTI results were longitudinally analyzed using a tract-specific analysis to measure the fractional anisotropy (FA) values of the entire corpus callosum (CC), as well as its genu, trunk, and splenium.
  
  
  RESULTS
  During the 52-week study period, seven patients developed psychosis (ARMS-P) and 39 did not (ARMS-NP). In the entire CC and the genu, trunk, and splenium of the CC, the FA values of the ARMS subjects were each significantly smaller than the respective values of the healthy controls at baseline. In the genu and trunk, the baseline FA values in the ARMS-NP group were, paradoxically, smaller than those of the ARMS-P group at baseline. Regarding the association between the FA values and psychiatric symptoms, a reduction in the FA value in the genu was significantly correlated with a deterioration of negative symptoms among the ARMS subjects.
  
  
  CONCLUSIONS
  Abnormal white matter integrity in the CC may predict the long-term outcome of patients with prodromal psychosis, since negative symptoms are associated with poor functioning.
authors.affiliation: Department of Neuropsychiatry, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Saito
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hori
authors.affiliation: Department of Neuropsychiatry, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Takahiro
authors.identifier: http://orcid.org/0000-0002-7318-7377
authors.initials: T
authors.lastname: Nemoto
authors.affiliation: Department of Neuropsychiatry, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Katagiri
authors.affiliation: Department of Diagnostic Radiology, Tokyo Metropolitan Geriatric Hospital, Tokyo, Japan.
authors.forename: Keigo
authors.initials: K
authors.lastname: Shimoji
authors.affiliation: Department of Social Medicine, Toho University School of Medicine, Tokyo, Japan.|Department of Public Health, Fukushima Medical University School of Medicine, Fukushima, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Ito
authors.affiliation: Department of Neuropsychiatry, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Naohisa
authors.initials: N
authors.lastname: Tsujino
authors.affiliation: Department of Neuropsychiatry, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Taiju
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Department of Radiology, Toho University Omori Medical Center, Tokyo, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Shiraga
authors.affiliation: Department of Radiology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Aoki
authors.affiliation: Department of Neuropsychiatry, Toho University School of Medicine, Tokyo, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Mizuno
mesh_terms: D000328:Adult; D016880:Anisotropy; D003337:Corpus Callosum / Q000473:pathology; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D059906:Neuroimaging; D062706:Prodromal Symptoms; D011618:Psychotic Disorders / Q000473:pathology*; D066127:White Matter / Q000473:pathology*; D055815:Young Adult
keywords: at-risk mental state; corpus callosum; diffusion tensor imaging; psychosis; schizophrenia