Showing papers by "Iris E. C. Sommer published in 2013"

Dopaminergic Function in the Psychosis Spectrum: An [18F]-DOPA Imaging Study in Healthy Individuals With Auditory Hallucinations

Abstract: Background: The psychosis phenotype appears to exist in the population as a continuum, but it is not clear if subclinical psychotic symptoms and psychotic disorders share the same neurobiology. We investigated whether the dopaminergic dysfunction seen in psychotic disorders is also present in healthy, well-functioning people with hallucinations. Methods: We compared dopamine synthesis capacity (using 6-[18F]fluoro-L-DOPA [[18F]-DOPA] positron emission tomography imaging) in 16 healthy individuals with frequent persistent auditory verbal hallucinations (hallucinating group) with that in 16 matched controls. Results: There was no significant difference in dopamine synthesis capacity in the striatum, or its functional subdivisions, between groups and no relationship between subclinical psychotic symptom severity or schizotypal traits and dopamine synthesis capacity in the hallucinating group. Conclusions: Altered dopamine synthesis capacity is unlikely to underlie subclinical hallucinations, suggesting that although there may be a phenomenological psychosis continuum, there are distinctions at the neurobiological level.

Aberrant resting-state connectivity in non-psychotic individuals with auditory hallucinations

Abstract: BackgroundAlthough auditory verbal hallucinations (AVH) are a core symptom of schizophrenia, they also occur in non-psychotic individuals, in the absence of other psychotic, affective, cognitive and negative symptoms. AVH have been hypothesized to result from deviant integration of inferior frontal, parahippocampal and superior temporal brain areas. However, a direct link between dysfunctional connectivity and AVH has not yet been established. To determine whether hallucinations are indeed related to aberrant connectivity, AVH should be studied in isolation, for example in non-psychotic individuals with AVH.MethodResting-state connectivity was investigated in 25 non-psychotic subjects with AVH and 25 matched control subjects using seed regression analysis with the (1) left and (2) right inferior frontal, (3) left and (4) right superior temporal and (5) left parahippocampal areas as the seed regions. To correct for cardiorespiratory (CR) pulsatility rhythms in the functional magnetic resonance imaging (fMRI) data, heartbeat and respiration were monitored during scanning and the fMRI data were corrected for these rhythms using the image-based method for retrospective correction of physiological motion effects RETROICOR.ResultsIn comparison with the control group, non-psychotic individuals with AVH showed increased connectivity between the left and the right superior temporal regions and also between the left parahippocampal region and the left inferior frontal gyrus. Moreover, this group did not show a negative correlation between the left superior temporal region and the right inferior frontal region, as was observed in the healthy control group.ConclusionsAberrant connectivity of frontal, parahippocampal and superior temporal brain areas can be specifically related to the predisposition to hallucinate in the auditory domain.

Cognitive biases and auditory verbal hallucinations in healthy and clinical individuals.

Abstract: Background. Several cognitive biases are related to psychotic symptoms, including auditory verbal hallucinations (AVH). It remains unclear whether these biases differ in voice-hearers with and without a 'need-for-care'. Method. A total of 72 healthy controls, 72 healthy voice-hearers and 72 clinical voice-hearers were compared on the Cognitive Biases Questionnaire for psychosis (CBQp), which assesses 'intentionalizing', ' jumping to conclusions', 'catastrophizing', 'dichotomous thinking' and 'emotional reasoning' in vignettes characterized by two themes, 'threatening events' and ` anomalous perceptions'. Results. Healthy voice-hearers scored intermediately on total CBQp between the control and clinical groups, differing significantly from both. However, on four out of five biases the scores of the healthy voice-hearers were comparable with those of the healthy controls. The only exception was 'emotional reasoning', on which their scores were comparable with the clinical group. Healthy voice-hearers demonstrated fewer biases than the psychotic patients on the ` threatening events', but not the 'anomalous perceptions', vignettes. CBQp scores were related to both cognitive and emotional, but not physical, characteristics of voices. Conclusions. Most cognitive biases prevalent in clinical voice-hearers, particularly with threatening events themes, are absent in healthy voice-hearers, apart from emotional reasoning which may be specifically related to the vulnerability to develop AVH. The association between biases and both beliefs about voices and distress/ emotional valence is consistent with the close links between emotions and psychotic phenomena identified by cognitive models of psychosis. The absence of reasoning biases might prevent the formation of threatening appraisals about anomalous experiences, thereby reducing the likelihood of distress and 'need for care'

How Frequent Are Radiological Abnormalities in Patients With Psychosis? A Review of 1379 MRI Scans

Abstract: BACKGROUND: The term psychosis refers to a combination of symptoms, without pointing to the origin of these symptoms. In a subset of psychotic patients, symptoms are attributable to an organic disease. It is important to identify these organic causes of psychosis early, as urgent treatment of the primary disease may be required. Some of these underlying organic disorders can be identified on magnetic resonance imaging (MRI) scans. Whether routine screening for all psychotic patients should therefore include MRI scans is still a matter of debate. METHODS: This study investigated the prevalence of clinically relevant abnormalities detected on MRI scans from psychotic patients and a matched control group. We could include MRI scans from 656 psychotic patients and 722 controls. The standard radiological reports of these scans were classified as normal, as a nonrelevant abnormality or as a clinically relevant brain abnormality by means of consensus, blind to diagnosis. RESULTS: A normal aspect of the brain was reported in 74.4% of the patients and in 73.4% of the controls. We found clinically relevant pathology in 11.1% of the patients and in 11.8% of the controls. None of the neuropathological findings observed in the patients was interpreted as a possible substrate for organic psychosis. Brain abnormalities that were classified as not clinically relevant were identified in 14.5% of the patients and in 14.8% of the controls. CONCLUSIONS: This suggests that MRI brain scans are not an essential part of routine screening for psychotic patients.

Functional Brain Imaging of Hallucinations: Symptom Capture Studies

Abstract: Hallucinations are defined as erroneous percepts that occur without any external sensory input. For decades, brain imaging has been extensively used to explore the neural substrates of hallucinations and propose new pathophysiological hypotheses for the schizophrenia spectrum. A reappraisal of the functional imaging procedures developed in the field allows conceptual distinction between two main study categories. Cognitive studies comparing hallucinators with nonhallucinators (i.e., trait studies), and state studies conducted during hallucinatory episodes; the latter category (e.g. capture studies) is of particular significance for our purpose because these studies directly measure brain activation associated with the onset of hallucinations. Because the available findings are difficult to summarize, here we report findings from a recent coordinate-based meta-analysis of the existing functional data on hallucinatory states. This quantitative review provides evidences for increased activity within the language network and the hippocampal formation during psychotic auditory verbal hallucinations. The role of primary and associative auditory cortices in hallucinations is critically discussed, and future research directions are considered.

Call for case histories of BMT in patients with coincident schizophrenia

Abstract: Recently, the case for an immune component in the etiology of schizophrenia has regained support,1, 2 leading to randomized controlled trials to explore treatment with immunosuppressive and anti-inflammatory drugs.3 Both postmortem4 and in-vivo studies5, 6 provided indications for an increased proinflammatory status in the brain of patients with recent-onset schizophrenia. A common characteristic of most, if not all, autoimmune diseases (AD) is their favorable response to immunoablation and rescue with BMT. It was established in radiation chimeras more than 50 years ago that the immunological and hematological systems have a common stem cell. In the wake of this discovery came a series of investigations into the role of the BM in autoimmune disorders (AD) demonstrating that both hereditary AD and the susceptibility for induced AD could be transferred by hematopoietic SCTs and that both forms of AD in experimental animals could be cured by an allogeneic BMT from healthy donors.7 We therefore searched among long-term survivors after allogeneic BMT (SCT) for patients with a coexisting AD at the time of the transplant. Up to 1998, case histories of a total of 22 such patients were retrieved, all but one of whom went into CR of their AD.8 These findings did not initiate treatment of AD patients with allogeneic BMT because of the high risks of this procedure. However, after it was demonstrated both in rats with induced systemic arthritis and in rats with an experimental allergic encephalomyelitis (a model for multiple sclerosis) that autologous BMTs were potentially equally effective as allogeneic transplants, this modality has been widely explored for treating refractory AD of all sorts.9 The European Group for Blood and Bone Marrow Transplantation (EBMT) estimates that worldwide around 3000 AD patients had been treated with autologous BMT; 1200 cases were entered in the EBMT database by June 2011.10 Overall, the 5-year survival rate of the first 900 cases analyzed was 85%, with 43% PFS. At present, around 50 000 hematopoietic SCT are registered annually. Considering a conservative prevalence estimate for schizophrenia of 8 per 1000, the registries can be expected to contain data on many survivors with coincident schizophrenia at the time of transplant. Information on the clinical course of schizophrenia after SCT would greatly enhance our understanding of the role of immune processes in schizophrenia. We have therefore asked the EBMT and the Center for Blood and Marrow Transplantation Research (CIBMTR) at the Medical College of Wisconsin about the feasibility of searching their databases for such cases. Simultaneously we call upon hematologists and psychiatrists to inform us directly of their relevant case histories. We are submitting this appeal to the respective professional journals and websites. We think this approach may save time and money in identifying cases that are not into the databases of the international registries. Please send the information about your cases, including identification numbers if registered, to one of us in Utrecht, E-mail: ln.thcertucmu@remmos.i

Call for case histories of BMT in patients with coincident schizophrenia

Abstract: Recently, the case for an immune component in the etiology of schizophrenia has regained support,1, 2 leading to randomized controlled trials to explore treatment with immunosuppressants and anti-inflammatory drugs.3 Both post-mortem4 and in-vivo studies5, 6 provided indications for an increased pro-inflammatory status in the brain of patients with recent-onset schizophrenia. A common characteristic of most if not all autoimmune diseases (AD) is their favourable response to immunoablation and rescue with bone marrow transplantation. It was established in radiation chimaeras more than 50 years ago that the immunological and hematological systems have a common stem cell. In the wake of this discovery came a strain of investigations into the role of the bone marrow in AD demonstrating that both hereditary AD and the susceptibility to induced AD could be transferred by hematopoietic stem cell transplants and that both forms of AD in experimental animals could be cured by an allogeneic BMT from healthy donors.7 Accordingly, the records of long-term survivors of an allogeneic bone marrow transplant (BMT) were searched for patients with a coexisting AD at the time of the transplant. Up to 1998, case histories of a total of 22 such patients were retrieved, all of whom except one went into complete remission of their AD.8 These findings did not initiate treatment of AD patients with allogeneic BMT because of the high risks of this procedure. However, after it was demonstrated both in rats with induced systemic arthritis and in rats suffering from experimental allergic encephalomyelitis (model for multiple sclerosis) that autologous bone marrow transplants were potentially equally effective as allogeneic transplants, this modality has been widely explored for treating refractory AD of all sorts.9 The European Group for Blood and Bone Marrow Transplantation (EBMT) estimates that, worldwide, around 3000 AD patients have since been treated with autologous BMT; 1200 cases were entered in their database by June 2011.10 Overall 5-year survival rate of the first 900 cases analysed was 85%, with 43% progression-free survival.