Longitudinal changes in the striatum and sub-threshold positive symptoms in individuals with an ‘at risk mental state’ (ARMS)

Poster B22, Tuesday, October 9, 11:30 am - 1:00 pm, Essex Ballroom

Naoyuki Katagiri1, Christos Pantelis2,3, Takahiro Nemoto1, Naohisa Tsujino1,5, Junichi Saito1,5, Masaaki Hori4, Taiju Yamaguchi1, Tomoyuki Funatogawa1, Masafumi Mizuno1; 1School of Medicine Faculty of Medicine, Toho University, 2Melbourne Neuropsychiatry Centre, Department of Psychiatry, The University of Melbourne & Melbourne, 3Centre for Neural Engineering, Department of Electrical and Electronic Engineering, University of Melbourne, 4Department of Radiology, Juntendo University School of Medicine, 5Saiseikai Yokohamashi Tobu Hospital Psychiatry

Background: The striatum is implicated as a crucial site for dopaminergic dysregulation in schizophrenia due to its high density in dopamine receptors. Recent studies have revealed that several psychotic symptom changes observed in ‘at risk mental state’ (ARMS) as well as schizophrenia are associated with changes in the striatum. While previous studies have focused on factors leading to exacerbation of symptoms and transition to full blown psychosis, we sought to investigate if structural changes in the striatum are associated with recovery of subthreshold positive psychotic symptoms in subjects with ARMS who did not develop psychosis (ARMS-N). Method: Sixteen healthy controls and 42 ARMS (37 ARMS-N) subjects participated this study. Striatal volume (bilateral caudate, putamen, and nucleus accumbens) were analyzed using magnetic resonance imaging. Subthreshold psychotic symptoms of the ARMS subjects were measured using the Scale of Prodromal Symptoms (SOPS). Imaging and symptoms were reevaluated in the ARMS group 52 weeks later. This study was approved by the Ethics Committee of the Toho University. Results: Significant right putamen volume reduction was observed at the 1-year follow-up in ARMS-N subjects. There was relationship between improvement in subthreshold psychotic symptoms and volume increase in a sub region of the striatum at follow-up. Conclusion: The association between improvement in subthreshold positive symptoms and an increase in volume in a sub region of striatum may suggest that changes in the striatum, which is a major site for dopamine innervation, are associated with symptom recovery.

Topic Area: Neurocognition

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