Altered Subcortical Volumes in Individuals at Risk for Psychotic Disorders

Poster B95, Tuesday, October 9, 11:30 am - 1:00 pm, Essex Ballroom

Daiki Sasabayashi1, Yoichiro Takayanagi1, Tsutomu Takahashi1, Naohiro Okada2, Shinsuke Koike2, Naoyuki Katagiri3, Chika Obara4, Hidenori Yamasue5, Kazunori Matsumoto4, Masafumi Mizuno3, Kiyoto Kasai2, Michio Suzuki1; 1Toyama University, 2Tokyo University, 3Toho University, 4Tohoku University, 5Hamamatsu University School of Medicine

1.Purpose: Previous structural magnetic resonance imaging (MRI) studies of psychotic disorders have shown volumetric alterations in the subcortical regions, which are involved in high-order cognition and emotional regulation. However, it remains elusive whether individuals at clinical high-risk for psychotic disorders, who have minimal confounding effects of medication and disease chronicity, exhibit subcortical volumetric changes. 2.Materials and Methods: T1-weighted MR scans were obtained from 107 individuals with at-risk mental state (ARMS), of whom 21 (19.6%) subsequently exhibited the transition to psychotic disorders during clinical follow-up, and 104 age- and gender- matched healthy subjects recruited at 4 scanning sites. Group differences in subcortical regional volumes (lateral ventricles, thalamus, caudate, putamen, globus pallidus, nucleus accumbens, hippocampus, and amygdala) were examined using FreeSurfer software. 3.Results: The ARMS group as a whole showed significantly larger volume for the caudate and pallidum in the left hemisphere and for bilateral lateral ventricles as compared with healthy controls. ARMS individuals were also characterized by left-greater-than-right asymmetries of the lateral ventricle, caudate, and pallidum. These changes were not related to medication dose and were also evident in drug-naïve ARMS subsample. There was no difference in the subcortical volumes between the ARMS with and without later transition to psychotic disorders. 4.Conclusion: Our findings suggested that left-dominant volume expansion of the caudate and pallidum in the ARMS subjects, which could not be explained only by medication effects, might be related to general vulnerability to psychopathology.

Topic Area: Ultra High Risk / Prodromal Research

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