Showing papers by "Iris E. C. Sommer published in 2011"
TL;DR: In this sample, the negative emotional valence of the content of AVHs could accurately predict the presence of a psychotic disorder in 88% of the participants, implying that inquiring after the emotional content ofAVHs may be a crucial step in the diagnosis of psychotic disorders in individuals hearing voices.
Abstract: Objective: Whereas auditory verbal hallucinations (AVHs) are most characteristic of schizophrenia, their presence has frequently been described in a continuum, ranging from severely psychotic patients to schizotypal personality disorder patients to otherwise healthy participants. It remains unclear whether AVHs at the outer borders of this spectrum are indeed the same phenomenon. Furthermore, specific characteristics of AVHs may be important indicators of a psychotic disorder. Method: To investigate differences and similarities in AVHs in psychotic and nonpsychotic individuals, the phenomenology of AVHs in 118 psychotic outpatients was compared to that in 11 otherwise healthy individuals, both experiencing AVHs at least once a month. The study was performed between September 2007 and March 2010 at the University Medical Center, Utrecht, the Netherlands. Characteristics of AVHs were quantified using the Psychotic Symptoms Rating Scales Auditory Hallucinations subscale. Results: The perceived location of voices (inside/outside the head), the number of voices, loudness, and personification did not differentiate between psychotic and healthy individuals. The most prominent differences between AVHs in healthy and psychotic individuals were the emotional valence of the content, the frequency of AVHs, and the control subjects had over their AVHs (all P values <.001). Age at onset of AVHs was at a significantly younger age in the healthy individuals (P <.001). In our sample, the negative emotional valence of the content of AVHs could accurately predict the presence of a psychotic disorder in 88% of the participants. Conclusions: We cannot ascertain whether AVHs at the outer borders of the spectrum should be considered the same phenomenon, as there are both similarities and differences. The much younger age at onset of AVHs in the healthy subjects compared to that in psychotic patients may suggest a different pathophysiology. The high predictive value of the emotional content of voices implies that inquiring after the emotional content of AVHs may be a crucial step in the diagnosis of psychotic disorders in individuals hearing voices. J Clin Psychiatry 2011;72(3):320-325 (C) Copyright 2011 Physicians Postgraduate Press, Inc.
270 citations
TL;DR: Although the observed effects are subtle, using high cannabidiol content cannabis was associated with significantly lower degrees of psychotic symptoms providing further support for the antipsychotic potential of cannABidiol.
209 citations
TL;DR: Low-frequency rTMS administered to the left TP or to the site of maximal hallucinatory activation is not more effective for medication-resistant AVH than sham treatment.
125 citations
TL;DR: Early start of cannabis use is strongly associated with subclinical psychotic symptoms and to a lesser degree with negative symptoms, while smoking high amounts of cannabis is associated with increased levels of all three symptom dimensions: psychotic, negative and depressive.
Abstract: Background Cannabis use is associated with psychosis and a range of subclinical psychiatric symptoms. The strength of this association depends on dosage and age at first use. The current study investigates whether level of cannabis exposure and starting age are associated with specific profiles of subclinical symptoms. Method We collected cross-sectional data from a young adult population sample by administering an online version of the Community Assessment of Psychic Experiences (CAPE). Cannabis exposure was quantified as the amount of Euros spent on cannabis per week and the age of initial cannabis use. The primary outcome measure was the odds ratio (OR) to belong to the highest 10% of scores on the total CAPE and the positive-, negative- and depressive symptom dimensions. Results In 17 698 adolescents (mean age 21.6, s.d.=4.2 years), cannabis use at age 12 years or younger was strongly associated with a top 10% score on psychotic experiences [OR 3.1, 95% confidence interval (CI) 2.1-4.3] and to a lesser degree with negative symptoms (OR 1.7, 95% CI 1.1-2.5). The OR of heavy users (>€25/week) for negative symptoms was 3.4 (95% CI 2.9-4.1), for psychotic experiences 3.0 (95% CI 2.4-3.6), and for depressive symptoms 2.8 (95% CI 2.3-3.3). Conclusions Early start of cannabis use is strongly associated with subclinical psychotic symptoms and to a lesser degree with negative symptoms, while smoking high amounts of cannabis is associated with increased levels of all three symptom dimensions: psychotic, negative and depressive. These results support the hypothesis that the impact of cannabis use is age specific.
104 citations
TL;DR: The combination of decreased FA and increased MTR values observed in the arcuate fasciculi in patients suggests increased free water concentrations, probably caused by degraded integrity of the axons or the supportive glia cells.
92 citations
TL;DR: As increased MTR in the arcuate fasciculus was present in both hallucinating groups, a specific association with AVH seems plausible, and a general decrease in fractional anisotropy for almost all bundles was observed in the patient group, but not in the non‐psychotic individuals withAVH.
Abstract: The pathophysiology of auditory verbal hallucinations (AVH) is still unclear. Cognitive as well as electrophysiological studies indicate that a defect in sensory feedback (corollary discharge) may contribute to the experience of AVH. This could result from disruption of the arcuate fasciculus, the major tract connecting frontal and temporo-parietal language areas. Previous diffusion tensor imaging studies indeed demonstrated abnormalities of this tract in schizophrenia patients with AVH. It is, however, difficult to disentangle specific associations with AVH in this patient group as many other factors, such as other positive and negative symptoms, medication or halted education could likewise have affected tract integrity. We therefore investigated AVH in relative isolation and studied a group of non-psychotic individuals with AVH as well as patients with AVH and non-hallucinating matched controls. We compared tract integrity of the arcuate fasiculus and of three other control tracts, between 35 non-psychotic individuals with AVH, 35 schizophrenia patients with AVH, and 36 controls using diffusion tensor imaging and magnetization transfer imaging. Both groups with AVH showed an increase in magnetization transfer ratio (MTR) in the arcuate fasciculus, but not in the other control tracts. In addition, a general decrease in fractional anisotropy (FA) for almost all bundles was observed in the patient group, but not in the non-psychotic individuals with AVH. As increased MTR in the arcuate fasciculus was present in both hallucinating groups, a specific association with AVH seems plausible. Decreases in FA, on the other hand, seem to be related to other disease processes of schizophrenia.
75 citations
TL;DR: The predisposition to experience AVH is associated with lower performance in executive functioning and aberrant language performance, which might be related to difficulties in the inhibition of irrelevant verbal information.
70 citations
TL;DR: This is the first study to report reduced LI at the onset of schizophrenia, before medical treatment is initiated, and it is revealed that this reduction was most prominent in the inferior frontal gyrus and the superior temporal gyrus.
45 citations
TL;DR: There is increasing evidence that a failure in corollary discharge, i.e., a neural signal originating in frontal speech areas that indicates to sensory areas that forthcoming thought is self-generated, may underlie the experience of auditory hallucinations.
Abstract: Electroencephalography (EEG) and magnetoencephalography (MEG) are two techniques that distinguish themselves from other neuroimaging methodologies through their ability to directly measure brain-related activity and their high temporal resolution. A large body of research has applied these techniques to study auditory hallucinations. Across a variety of approaches, the left superior temporal cortex is consistently reported to be involved in this symptom. Moreover, there is increasing evidence that a failure in corollary discharge, i.e. a neural signal originating in frontal speech areas that indicates to sensory areas that forthcoming thought is self-generated, may underlie the experience of auditory hallucinations
43 citations
TL;DR: The results suggest that fTCD can be a valid alternative for fMRI to measure lateralization, particularly when costs or mobility are important factors in the study design.
Abstract: Cerebral language lateralization can be assessed in several ways. In healthy subjects, functional MRI (fMRI) during performance of a language task has evolved to be the most frequently applied method. Functional Transcranial Doppler (fTCD) may provide a valid alternative, but has been used rarely. Both techniques have their own strengths and weaknesses and as a result may be applied in different fields of research. Until now, only one relatively small study (n=13) investigated the correlation between lateralization indices measured by fTCD and fMRI and showed a remarkably high correlation. To further evaluate the correlation between lateralization indices measured with fTCD and fMRI, we compared lateralization indices of twenty-two healthy subjects (twelve left- and ten right-handed) using the same word generation paradigm for the fTCD as for the fMRI experiment. Lateralization indices measured with fTCD were highly but imperfectly correlated with lateralization indices measured with fMRI (Spearman’s rho=0.75, p<0.001). The imperfectness of the correlation can partially be explained by methodological restrictions of fMRI as well as fTCD. Our results suggest that fTCD can be a valid alternative for fMRI to measure lateralization, particularly when costs or mobility are important factors in the study design.
41 citations
TL;DR: The association between cannabis and psychiatric hospitalization is studied in detail in order to establish a cause-and-effect relationship.
Abstract: Objective: To investigate the relationship between cannabis use and mental health. Method: A cross‐sectional analysis in a sample of 17 698 individuals with a mean age of 22 years (SD: 4.2). Participants provided information on the amount and initial age of cannabis use and history of psychiatric hospitalizations through a web‐based questionnaire. To quantify Δ9‐tetrahydrocannabinol exposure, we operationalized cannabis use as the amount of money spent on cannabis per week over the last month. The odds ratio of having a history of psychiatric hospitalizations was the primary outcome measure. Results: We found a dose-response relationship between the amount of cannabis use and the odds for psychiatric hospitalization. Adjusted odds ratios for hospitalization increased with the amount of cannabis consumed from 1.6 (95% CI: 1.1-2.3) in incidental users to 6.2 (95% CI: 4.3-8.9) in heavy users (>€25/week). Our data suggested that concomitant drug use was an intermediate factor. Exposure to cannabis before the age of 12 years was found to carry a 4.8 (95% CI: 2.9-7.8) times increased odds for past psychiatric hospitalizations. Conclusion: We conclude that early and heavy uses of cannabis are each and independently associated with poor mental health in its users.
TL;DR: This case indicates that VAHs and metamorphopsias in AIWS are associated with synchronized activation in both auditory and visual cortices, and indicates that local rTMS treatment may have global therapeutic effects, suggesting an effect on multiple brain regions in a distributed network.
Abstract: Background: Alice in Wonderland syndrome (AIWS) is a rare cluster of CNS symptoms characterized by visual distortions (i.e. metamorphopsias), body image distortions, time distortion
Journal Article•
TL;DR: The necessity to reappraise the concepts of auditory hallucinations developed during the era of classic psychiatry to incorporate them into the current nomenclature and classification of auditory hallucination, and to test them empirically with the aid of the structural and functional imaging techniques currently available is underscored.
Abstract: Background We are rapidly increasing our knowledge about the correlates of auditory hallucinations. If we are to understand and integrate this new knowledge it is essential that the nomenclature for this special area is clear and unambiguous. Aim To review and to re-evaluate the concept of auditory hallucinations belonging to classical psychiatry. Method Relevant data were collected from books, PubMed, Embase and the Cochrane Library. Results On the basis of our findings we present different classifications for auditory hallucinations. Conclusions Our review emphasises the need for a re-appraisal of these concepts, clearer definitions and an improved nomenclature. These will make it easier to set up, conduct and interpret neurological studies of these frequently occurring phenomena.
TL;DR: In this paper, the authors used functional imaging to determine the SIDE for rTMS stimulation and found that the side where activation was most pronounced was the left side of the brain.