Papers by Carolin Opgen-Rhein
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The chromosomal region coding for D-amino acid oxidase activator (DAOA) on chromosome 13q has ext... more The chromosomal region coding for D-amino acid oxidase activator (DAOA) on chromosome 13q has extensively been investigated as a susceptibility locus for schizophrenia. Evidence from linkage and association studies is promising, and the proposed function of the gene and protein intriguingly matches current hypotheses on the aetiology of the illness. Furthermore, association of the gene with both schizophrenia and affective bipolar disorder seems to bridge a long-standing gap between the two major mental illnesses in terms of diagnostic classification and aetiology. However, replication of association findings has proved difficult, and multiple association studies have left the actual risk-conferring variant elusive. In vitro studies have yielded conflicting results about the specific intracellular function and location of the proposed gene product, the protein LG72. The aim of this article is to provide an overview with regard to current association findings and proceedings in knowledge concerning the biological relevance of the gene and its impact on the development of schizophrenia and on related phenotypes.
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The elaboration of the concept of cycloid psychoses has been a major focus in the work of Karl Le... more The elaboration of the concept of cycloid psychoses has been a major focus in the work of Karl Leonhard [10]. According to his view, cycloid psychoses are a group of nosologically distinct disorders and are to be distinguished from schizophrenic as well as affective psychoses in terms of clinical course, therapy, and outcome. There is a certain similarity with the group of unsystemat
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Background: Vagus nerve stimulation (VNS) is a new therapy option for treatment of otherwise ther... more Background: Vagus nerve stimulation (VNS) is a new therapy option for treatment of otherwise therapy-refractory major depressive disorder. However, the mechanism of central nervous action is poorly understood. Electroencephalographic (EEG) studies may be of interest since chronic peripheral current application to the vagus nerve may exert lasting neurophysiologically detectable effects on central electrical activity. In an exploratory study, we investigated the effects of VNS on auditory event-related potentials (ERP). Methods: Thirteen depressive patients (mean Hamilton depression score (HAMD) at baseline=24.2) receiving VNS were investigated prior to implantation and 10 weeks after standard cycling VNS. Stimulation intensity was 0.94±0.46 mA, pulse width 0.250 μs, and frequency 20 Hz. 1 h prior to follow-up investigation, VNS was turned off. Auditory ERP were elicited using a standard auditory oddball paradigm and were recorded with 29-channel EEG. Results: Post VNS, grand average...
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Schizophrenia Research, 2010
In a previous study, we found a reduced amplitude modulation of the visual P3 component of the ev... more In a previous study, we found a reduced amplitude modulation of the visual P3 component of the event-related potential (ERP) in schizophrenic patients compared with healthy controls during inhibition in the Attention Network Test (ANT). The objective of the present study was to replicate this finding and to explore whether this cortical processing deficit is specific to schizophrenia. Sixteen schizophrenic patients, sixteen depressive patients, and sixteen healthy controls matched for age, sex, and education were included. Participants were tested with the ANT, a test of selective attention that provides behavioral estimates for alerting, orienting, and inhibition. 32-Channel electroencephalogram was recorded and visual P3 amplitudes were topographically analyzed and compared between groups. There were no significant behavioral between-group differences in terms of mean reaction time, accuracy, and ANT effects alerting, orienting, and inhibition. Absolute visual P3 amplitude was not reduced in schizophrenia or depression. P3 amplitude modulation was defined as P3 amplitude at Pz as a function of ANT flanker conditions. We found a parietal P3 amplitude modulation deficit in schizophrenic patients (-.015) that was absent in both healthy controls (-.705; p = .002) and depressive patients (-1.022; p = .001). The results provide evidence that a deficit of visual P3 amplitude modulation distinguishes schizophrenia from healthy and disease controls and provides greater discriminative power than absolute visual P3 amplitude.
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Schizophrenia Research, 2011
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Schizophrenia Research, 2009
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Schizophrenia Bulletin, 2008
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Psychiatry Research, 2009
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Pharmacopsychiatry, 2007
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Pharmacopsychiatry, 2004
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The Pharmacogenomics Journal, 2006
Clozapine-induced agranulocytosis (CA) is still among the least understood adverse drug reactions... more Clozapine-induced agranulocytosis (CA) is still among the least understood adverse drug reactions in psychopharmacology. In particular, its genetic background is far from being clarified. Within the framework of a case-control study, we performed human leukocyte antigen (HLA) genotyping and haplotype analyses in 42 non-Jewish Caucasian schizophrenic patients (N=42) suffering from CA and 75 non-Jewish Caucasian schizophrenic patients treated with clozapine without developing CA. While controlling for age (P<0.0001) and sex (P=0.835), testing of the alleles from both HLA-loci resulted in borderline results for Cw2 (P=0.085, odds ratio (OR)=0.36, 95% confidence interval (CI): 0.08-1.23), Cw7 (P=0.058, OR=2.0, 95% CI: 0.87-4.63) and DRB5*0201 (P=0.005, adjusted OR=22.15). For haplotype analysis, we obtained significant association results with CA for the two-locus haplotypes HLA-Cw-B (P=0.022) and HLA-DRB5-DRB4 (P=0.050), and for the three-locus haplotype HLA-Cw-B-DRB5 (P=0.030). The complex nature of CA implies that many genes might play a role, but currently, only HLA associations with CA are identified as clinically relevant.
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Multiple Sclerosis Journal, 2009
Attention is one of the cognitive domains typically affected in multiple sclerosis. The Attention... more Attention is one of the cognitive domains typically affected in multiple sclerosis. The Attention Network Test was developed to measure the function of the three distinct attentional networks, alerting, orienting, and executive control. The Attention Network Test has been performed in various neuropsychiatric conditions, but not in multiple sclerosis. Our objective was to investigate functions of attentional networks in multiple sclerosis by means of the Attention Network Test. Patients with relapsing—remitting multiple sclerosis (n = 57) and healthy controls (n = 57) matched for age, sex, and education performed the Attention Network Test. Significant differences between patients and controls were detected in the alerting network (p = 0.003), in contrast to the orienting (p = 0.696) and the conflict (p = 0.114) network of visual attention. Mean reaction time in the Attention Network Test was significantly longer in multiple sclerosis patients than in controls (p = 0.032), Multiple ...
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Journal of Psychiatric Research, 2007
Schizophrenia research has gained a new focus on identification and further characterization of n... more Schizophrenia research has gained a new focus on identification and further characterization of neurocognitive deficits in the search for behavioural endophenotypes of this disorder. The objective of this study was to explore differential cortical processing during executive control in schizophrenia as assessed with the attention network test (ANT). Sixteen schizophrenic patients and sixteen healthy controls matched for gender, age, education, and nicotine consumption were tested with the ANT while recording 29-channel-electroencephalogram (EEG). Visual event-related potentials (ERP) N200 and P300 were topographically analyzed and cortical mapping using low resolution brain electromagnetic tomography (LORETA) was applied to localize neuroelectric generators of ERP. Behaviourally, significant differences between schizophrenic patients and controls were found only for the conflict condition (p<0.05) and for conflict adjusted by mean reaction time (p<0.01). Examining ERP of control subjects, N200 failed to show robust flanker congruency effects. P300 amplitude was reduced at Pz (p<0.05) and P300 latency was increased at Cz (p<0.005) for the conflict condition. Schizophrenic patients differed significantly in P300 latency at Cz during late conflict processing (p<0.005). Source analysis revealed a deficit in anterior cingulate cortex (p<0.05). Our results are in line with previous reports about dysfunctional ACC activation in schizophrenia and argue in favour of a selective deficit of cortical conflict resolution. It is further proposed that dysfunctional ACC activation during executive processing may be a neurophysiologic endophenotype candidate of schizophrenia.
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Papers by Carolin Opgen-Rhein