title: The Vulnerability to Suicidal Behavior is Associated with Reduced Connectivity Strength.
abstract: Suicidal behavior constitutes a major public health problem. Based on the stress-diathesis model, biological correlates of a diathesis might help to predict risk after stressor-exposure. Structural changes in cortical and subcortical areas and their connections have increasingly been linked with the diathesis. The current study identified structural network changes associated with a diathesis using a whole-brain approach by examining the structural connectivity between regions in euthymic suicide attempters (SA). In addition, the association between connectivity measures, clinical and genetic characteristics was investigated. We hypothesized that SA showed lower connectivity strength, associated with an increased severity of general clinical characteristics and an elevated expression of short alleles in serotonin polymorphisms. Thirteen euthymic SA were compared with fifteen euthymic non-attempters and seventeen healthy controls (HC). Clinical characteristics and three serotonin-related genetic polymorphisms were assessed. Diffusion MRI together with anatomical scans were administered. Preprocessing was performed using Explore DTI. Whole brain tractography of the diffusion-weighted images was followed by a number of streamlines-weighted network analysis using NBS. The network analysis revealed decreased connectivity strength in SA in the connections between the left olfactory cortex and left anterior cingulate gyrus. Furthermore, SA had increased suicidal ideation, hopelessness and self-reported depression, but did not show any differences for the genetic polymorphisms. Finally, lower connectivity strength between the right calcarine fissure and the left middle occipital gyrus was associated with increased trait anxiety severity (rs = -0.78, p < 0.01) and hopelessness (rs = -0.76, p < 0.01). SA showed differences in white matter network connectivity strength associated with clinical characteristics. Together, these variables could play an important role in predicting suicidal behavior.
authors.affiliation: Unit for Suicide Research, Department of Psychiatry and Medical Psychology, Ghent University Ghent, Belgium.
authors.forename: Stijn
authors.initials: S
authors.lastname: Bijttebier
authors.affiliation: School of Psychology, Faculty of Health Sciences, Australian Catholic University Melbourne, VIC, Australia.
authors.forename: Karen
authors.initials: K
authors.lastname: Caeyenberghs
authors.affiliation: Department of Psychiatry, AZ Sint-Jan Brugge-Oostende AV Brugge, Belgium.
authors.forename: Hans
authors.initials: H
authors.lastname: van den Ameele
authors.affiliation: Department of Radiology and Nuclear Medicine, Ghent University Ghent, Belgium ; Ghent Institute for Functional and Metabolic Imaging (GIfMI), Ghent University Ghent, Belgium.
authors.forename: Eric
authors.initials: E
authors.lastname: Achten
authors.affiliation: Universitätsklinik und Poliklinik für Psychiatrie, Psychotherapie und Psychosomatik, Martin-Luther-Universität Halle-Wittenberg Halle/Saale, Germany.
authors.forename: Dan
authors.initials: D
authors.lastname: Rujescu
authors.affiliation: Department of Psychiatry, AZ Groeninge Kortrijk, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Titeca
authors.affiliation: Unit for Suicide Research, Department of Psychiatry and Medical Psychology, Ghent University Ghent, Belgium.
authors.forename: Cornelis
authors.initials: C
authors.lastname: van Heeringen
keywords: 5-HTTLPR; MAOA; connectivity strength; network based analysis; predisposition; suicidal behavior; whole brain tractography