title: Glutamate as a mediating transmitter for auditory hallucinations in schizophrenia: a (1)H MRS study.
abstract: This is a (1)H MR spectroscopy (MRS) study of glutamate (Glu), measured as Glx, levels in temporal and frontal lobe regions in patients with schizophrenia compared with a healthy control group with the objective of revealing aspects of the underlying neurochemistry of auditory hallucinations. We further compared and correlated Glu(Glx) levels for the patients-only against frequency and severity of auditory hallucinations and the sum of Positive symptoms, and also for frequency and severity of emotional withdrawal, and sum of Negative symptoms. The sample included 23 patients with an ICD-10 and DSM-IV diagnosis of schizophrenia, and 26 healthy control subjects without any known psychiatric or neurological disorders. Symptom scores were obtained from the Positive and Negative Syndrome Scale (PANSS). (1)H MRS data were acquired on a 3T MR scanner from two temporal and two frontal voxels, using standard sequences and analysis parameters. The results showed that schizophrenia patients as a group had reduced Glu(Glx) levels in the voxels of interest compared to the healthy control subjects, while increased levels were found for patients with frequent and severe auditory hallucinations, relative to patients with less frequent and severe hallucination. We further found significant positive correlations between frequency and severity of auditory hallucinations, and for sum Positive symptoms, and Glu(Glx) levels in all regions, not seen when the analysis was done for negative symptoms. It is concluded that the results show for the first time that glutamate may be a mediating factor in auditory hallucinations in schizophrenia.
authors.affiliation: Department of Biological and Medical Psychology, University of Bergen, Norway; Division of Psychiatry, Haukeland University Hospital, Bergen, Norway; Department of Radiology, Haukeland University Hospital, Bergen, Norway; NORMENT Center of Excellence, University of Oslo and Oslo University Hospital, Norway. Electronic address: hugdahl@psybp.uib.no.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Hugdahl
authors.affiliation: Department of Biological and Medical Psychology, University of Bergen, Norway.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Craven
authors.affiliation: Department of Biological and Medical Psychology, University of Bergen, Norway.
authors.forename: Merethe
authors.initials: M
authors.lastname: Nygård
authors.affiliation: Division of Psychiatry, Haukeland University Hospital, Bergen, Norway; Department of Clinical Psychology, University of Bergen, Norway.
authors.forename: Else-Marie
authors.initials: EM
authors.lastname: Løberg
authors.affiliation: Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.
authors.forename: Jan Øystein
authors.initials: JØ
authors.lastname: Berle
authors.affiliation: Division of Psychiatry, Haukeland University Hospital, Bergen, Norway; Section of Psychiatry, Department of Clinical Medicine, University of Bergen, Bergen, Norway.
authors.forename: Erik
authors.initials: E
authors.lastname: Johnsen
authors.affiliation: Division of Psychiatry, Haukeland University Hospital, Bergen, Norway.
authors.forename: Rune
authors.initials: R
authors.lastname: Kroken
authors.affiliation: Department of Biological and Medical Psychology, University of Bergen, Norway; Department of Clinical Engineering, Haukeland University Hospital, Bergen, Norway.
authors.forename: Karsten
authors.initials: K
authors.lastname: Specht
authors.affiliation: Division of Mental Health and Addiction, Oslo University Hospital & Institute of Clinical Medicine, University of Oslo, Norway; NORMENT Center of Excellence, University of Oslo and Oslo University Hospital, Norway.
authors.forename: Ole A
authors.initials: OA
authors.lastname: Andreassen
authors.affiliation: Department of Clinical Engineering, Haukeland University Hospital, Bergen, Norway.
authors.forename: Lars
authors.initials: L
authors.lastname: Ersland
mesh_terms: D000704:Analysis of Variance; D001921:Brain / Q000378:metabolism*; D001931:Brain Mapping; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D006212:Hallucinations / Q000209:etiology* / Q000473:pathology*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D011522:Protons; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000150:complications*
chemical_list: D011522:Protons; D018698:Glutamic Acid
keywords: MR; MR spectroscopy; auditory hallucinations; glutamate; schizophrenia