White matter microstructure and network-connectivity in emerging adults with subclinical psychotic experiences

Stijn Michielse,Jindra Bakker,Therese Van Amelsvoort,Iris Lange,Ritsaert Lieverse,Koen Schruers,Machteld Marcelis,Liesbet Goossens,Simone Verhagen,Marieke Wichers,Jim Van Os

doi:10.1007/s11682-019-00129-0

Abstract

Group comparisons of individuals with psychotic disorder and controls have shown alterations in white matter microstructure. Whether white matter microstructure and network connectivity is altered in adolescents with subclinical psychotic experiences (PE) at the lowest end of the psychosis severity spectrum is less clear. DWI scan were acquired in 48 individuals with PE and 43 healthy controls (HC). Traditional tensor-derived indices: Fractional Anisotropy, Axial Diffusivity, Mean Diffusivity and Radial Diffusivity, as well as network connectivity measures (global/local efficiency and clustering coefficient) were compared between the groups. Subclinical psychopathology was assessed with the Community Assessment of Psychic Experiences (CAPE) and Montgomery–Åsberg Depression Rating Scale (MADRS) questionnaires and, in order to capture momentary subclinical expression of psychosis, the Experience Sampling Method (ESM) questionnaires. Within the PE-group, interactions between subclinical (momentary) symptoms and brain regions in the model of tensor-derived indices and network connectivity measures were investigated in a hypothesis-generating fashion. Whole brain analyses showed no group differences in tensor-derived indices and network connectivity measures. In the PE-group, a higher positive symptom distress score was associated with both higher local efficiency and clustering coefficient in the right middle temporal pole. The findings indicate absence of microstructural white matter differences between emerging adults with subclinical PE and controls. In the PE-group, attenuated symptoms were positively associated with network efficiency/cohesion, which requires replication and may indicate network alterations in emerging mild psychopathology.

Highlights

Over the last decades, white matter ‘integrity’ alterations have been frequently reported as a neural characteristic associated with psychotic disorder (Fornito et al 2012; Friston 1999; Stephan et al 2009)
Previous research on patients with psychotic disorder suggests that axonal density (AXD) is unaffected (Kikinis et al 2015; Reid et al 2016; Scheel et al 2013), whereas radial diffusivity (RAD) and mean diffusivity (MD) may be increased with respect to controls (Ardekani et al 2011; Clark et al 2011; Zeng et al 2016)
A total of 48 participants were included in the psychotic experiences (PE)-group and 43 in the healthy control (HC)-group

Summary

Introduction

White matter ‘integrity’ alterations have been frequently reported as a neural characteristic associated with psychotic disorder (Fornito et al 2012; Friston 1999; Stephan et al 2009). Lower AXD and increased RAD have respectively been related to a lower number of axons and decreased myelin content Previous research on patients with psychotic disorder suggests that AXD is unaffected (Kikinis et al 2015; Reid et al 2016; Scheel et al 2013), whereas RAD and MD may be increased with respect to controls (Ardekani et al 2011; Clark et al 2011; Zeng et al 2016).

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Results

Conclusion