PM459. Brain Network Characteristics of Individuals at Clinical High Risk for Psychosis in between Normality and Psychosis: A Combined Structural and Functional Imaging Study

s | 67 PM459 Brain Network Characteristics of Individuals at Clinical High Risk for Psychosis in between Normality and Psychosis: A Combined Structural and Functional Imaging Study Soo-Hee Choi, Jun Soo Kwon Seoul National University, Republic of Korea Abstract Objective: In an effort to improve early recognition and intervention in patients with schizophrenia (SZ), individuals at clinical high risk for psychosis (CHR) have been the focus of clinical attention. To distinguish the prodrome of psychosis from transient disturbance of mental state in youth, the authors classified broad spectrum of CHR state into two subgroups according to neurobiological characteristics using the structural and functional network constructs. Method: Structural diffusion tensor imaging and resting-state functional magnetic resonance imaging were scanned in 61healthy controls (HC), 57 individuals at CHR and 29 patients with SZ. The main outcome was a likelihood ratio using measures of structural and functional network efficiencies, coupling strength of the structural and functional networks, disease-specific data analysis using the both network constructs to obtain the most probable classification of CHR into HC or SZ. Results: Likelihood ratios revealed that 33 individuals at CHR were likely close to HC (CHR-HC) and the rest of 24 CHRs were close to SZ (CHR-SZ). CHR subgroups were comparable to each other in demographic characteristics and clinical symptoms. However, verbal functions of CHRCON were akin to CON and those of CHRSZ were akin to SZ. Additionally, CHR-SZ had lower verbal intelligence than CHR-HC. Conclusions: Our findings provide novel neurobiological evidence that heterogeneous CHR population can be divided into subgroups, one of which is more likely to be prone to psychosis. Using a combination of structural and functional data, we could detect vulnerable population and provide an active intervention in early phase of CHR state.Objective: In an effort to improve early recognition and intervention in patients with schizophrenia (SZ), individuals at clinical high risk for psychosis (CHR) have been the focus of clinical attention. To distinguish the prodrome of psychosis from transient disturbance of mental state in youth, the authors classified broad spectrum of CHR state into two subgroups according to neurobiological characteristics using the structural and functional network constructs. Method: Structural diffusion tensor imaging and resting-state functional magnetic resonance imaging were scanned in 61healthy controls (HC), 57 individuals at CHR and 29 patients with SZ. The main outcome was a likelihood ratio using measures of structural and functional network efficiencies, coupling strength of the structural and functional networks, disease-specific data analysis using the both network constructs to obtain the most probable classification of CHR into HC or SZ. Results: Likelihood ratios revealed that 33 individuals at CHR were likely close to HC (CHR-HC) and the rest of 24 CHRs were close to SZ (CHR-SZ). CHR subgroups were comparable to each other in demographic characteristics and clinical symptoms. However, verbal functions of CHRCON were akin to CON and those of CHRSZ were akin to SZ. Additionally, CHR-SZ had lower verbal intelligence than CHR-HC. Conclusions: Our findings provide novel neurobiological evidence that heterogeneous CHR population can be divided into subgroups, one of which is more likely to be prone to psychosis. Using a combination of structural and functional data, we could detect vulnerable population and provide an active intervention in early phase of CHR state. PM460 Association between increased resting-state functional connectivity and reduced symptoms of schizotypal personality disorder: neural evidence for compensatory brain responses Ji-Won Hur1,2, Kang Ik Kevin Cho1, Wi Hoon Jung3, Tae Young Lee4, Sung Nyun Kim5, Jun Soo Kwon1,5* 1 Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea 2 Department of Psychology, College of Social Sciences, Chung-Ang University, Seoul, Republic of Korea 3 Department of Psychology, University of Pennsylvania, Pennsylvania, United States 4 Department of Neuropsychiatry, Seoul National University Hospital, Seoul, Republic of Korea 5 Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea Abstract Objective: Schizotypal personality disorder (SPD) shares genetic susceptibilities and clinical features with schizophrenia. Despite growing interest for resting functional connectivity networks of schizophrenia, little is known to date about resting–connectivity networks of, and their contributions to the SPD. The current study aimed to examine the resting-state default mode network (DMN) functional connectivity in individuals with SPD. Method: Twenty-five individuals with SPD and 38 normal controls underwent resting-state functional magnetic resonance imaging. We compared group differences for resing-state connectivity and then explored the links between altered connectivity and clinical symptoms in SPD subjects. Results: As a result, both ROI-to-ROI and seed based analysis revealed that during resting state, the SPD group demonstrated increased connectivity from the left middle frontal gyrus to the posterior cingulate cortex compared to the normal controls. In addition, connectivity between the left parahippocampal gyrus and left middle frontal gyrus (ROIs analysis), as well as between the bilateral anterior cingulate cortex and posterior cingulate cortex (whole brain analysis), were also identified. In particular, enhanced middle frontal connectivity was negatively correlated with ideas of references and unusual perceptual experiences of SPD subjects. Conclusions: The current study suggests the first neural evidence of an enhanced functional network with middle frontal regions across the resting–state network in SPD, compared to that of controls. Furthermore, these alterations may possibly take role in compensating for their clinical symptoms including thought disorder and perceptual aberrations in SPD. Our imaging evidence may provide insight on the neurocompensatory responses observed in schizophrenia spectrums.