title: The Loudness Dependence of Auditory Evoked Potentials (LDAEP) in individuals at risk for developing bipolar disorders and schizophrenia.
abstract: OBJECTIVE
  The Loudness Dependence of Auditory Evoked Potentials (LDAEP) is considered as an indicator of central serotonergic activity. Alteration of serotonergic neurotransmission was reported in bipolar disorders and schizophrenia. In line with previous reports on clinically manifest disorders, we expected a weaker LDAEP in subjects at risk for bipolar disorders and schizophrenia compared to healthy controls.
  
  
  METHODS
  We analyzed LDAEP of individuals at risk for developing bipolar disorders (n=27), with high-risk status (n=74) and ultra-high-risk status for schizophrenia (n=86) and healthy controls (n=47).
  
  
  RESULTS
  The LDAEP did not differ between subjects at risk for schizophrenia or bipolar disorders and controls. Among subjects without medication (n=122), the at-risk-bipolar group showed a trend towards a weaker LDAEP than both the high-risk and the ultra-high-risk groups for schizophrenia.
  
  
  CONCLUSIONS
  The LDAEP did not appear as a vulnerability marker for schizophrenia or bipolar disorders. This suggests that an altered LDAEP may not be measurable until the onset of clinically manifest disorder. However, the hypothesis that pathogenic mechanisms leading to bipolar disorders may differ from those leading to schizophrenia is supported.
  
  
  CONCLUSIONS
  This is the first study investigating LDAEP in a population at risk for bipolar disorders.
authors.affiliation: The Zurich Program for Sustainable Development of Mental Health Services (ZInEP), University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland; Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Florence
authors.initials: F
authors.lastname: Hagenmuller
authors.affiliation: The Zurich Program for Sustainable Development of Mental Health Services (ZInEP), University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland; Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Karsten
authors.initials: K
authors.lastname: Heekeren
authors.affiliation: The Zurich Program for Sustainable Development of Mental Health Services (ZInEP), University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Magali
authors.initials: M
authors.lastname: Meier
authors.affiliation: The Zurich Program for Sustainable Development of Mental Health Services (ZInEP), University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland; Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Theodoridou
authors.affiliation: The Zurich Program for Sustainable Development of Mental Health Services (ZInEP), University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland; Department of Child and Adolescent Psychiatry, University of Zurich, Zurich, Switzerland.
authors.forename: Susanne
authors.initials: S
authors.lastname: Walitza
authors.affiliation: The Zurich Program for Sustainable Development of Mental Health Services (ZInEP), University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland; Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland.
authors.forename: Helene
authors.initials: H
authors.lastname: Haker
authors.affiliation: The Zurich Program for Sustainable Development of Mental Health Services (ZInEP), University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland; Institute of Psychiatry, Laboratory of Neuroscience (LIM 27), University of Sao Paulo, Brazil.
authors.forename: Wulf
authors.initials: W
authors.lastname: Rössler
authors.affiliation: The Zurich Program for Sustainable Development of Mental Health Services (ZInEP), University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland; Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry Zurich, University of Zurich, Zurich, Switzerland. Electronic address: wolfram.kawohl@puk.zh.ch.
authors.forename: Wolfram
authors.initials: W
authors.lastname: Kawohl
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000293:Adolescent; D000328:Adult; D001303:Auditory Cortex / Q000503:physiopathology; D001714:Bipolar Disorder / Q000209:etiology / Q000503:physiopathology*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008144:Loudness Perception / Q000502:physiology*; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D012559:Schizophrenia / Q000209:etiology / Q000503:physiopathology*; D055815:Young Adult
keywords: Bipolar disorders; Dipole source analysis; Primary auditory cortex; Risk; Schizophrenia; Serotonin