The estrogen hypothesis for schizophrenia suggests neuroprotective effects of estrogen for the development of the disorder and for symptom severity, including auditory hallucinations. Furthermore, estrogen has shown enhancing effects on cognitive control, a function that is also implicated in auditory hallucinations. Whether estrogen affects the tendency to hallucinate in healthy participants, and the potential mediating role of cognitive control, has not yet been studied.
View Article and Find Full Text PDFObjectives: Negative emotional valence of auditory verbal hallucinations (AVHs) in schizophrenia can be a source of distress and is considered a strong predictor of illness severity. Previous studies have found glutamate to mediate AVH severity in frontal and temporal brain regions, however, they do not specifically address emotional valence of AVH. The role of glutamate for the experience of negative- versus positive emotional valence of AVH is therefore unknown and was investigated in the current study.
View Article and Find Full Text PDFHallucinatory experiences (HEs) can be pronounced in psychosis, but similar experiences also occur in nonclinical populations. Cognitive mechanisms hypothesized to underpin HEs include dysfunctional source monitoring, heightened signal detection, and impaired attentional processes. Using data from an international multisite study on non-clinical participants (N = 419), we described the overlap between two sets of variables - one measuring cognition and the other HEs - at the level of individual items.
View Article and Find Full Text PDFOlfactory hallucinations referring to olfactory perceptions in the absence of chemical stimuli, occur in non-clinical and clinical populations. Few studies have investigated their prevalence in the general population and little is known about factors triggering and maintaining them such as substance use, severe life events, and mood. We analyzed self-report data from 2500 community dwelling Norwegians, aged 18-96 years, for occurrence of olfactory hallucinations and co-occurring hallucinations in other modalities (auditory, visual, tactile).
View Article and Find Full Text PDFHallucinatory experiences can occur in both clinical and nonclinical groups. However, in previous studies of the general population, investigations of the cognitive mechanisms underlying hallucinatory experiences have yielded inconsistent results. We ran a large-scale preregistered multisite study, in which general-population participants ( = 1,394 across 11 data-collection sites and online) completed assessments of hallucinatory experiences, a measure of adverse childhood experiences, and four tasks: source memory, dichotic listening, backward digit span, and auditory signal detection.
View Article and Find Full Text PDFBackground: Few studies have investigated hallucinations that occur at the onset/offset of sleep (called hypnagogic/hypnopompic hallucinations; HHHs), despite the fact that their prevalence in the general population is reported to be higher than the prevalence of daytime hallucinations. We utilized data from an epidemiological study to explore the prevalence of HHHs in various modalities. We also investigated phenomenological differences between sleep-related (HHHs) and daytime hallucinations in the auditory modality.
View Article and Find Full Text PDFGlutamate (Glu), gamma amino-butyric acid (GABA), and excitatory/inhibitory (E/I) imbalance have inconsistently been implicated in the etiology of schizophrenia. Elevated Glu levels in language regions have been suggested to mediate auditory verbal hallucinations (AVH), the same regions previously associated with neuronal hyperactivity during AVHs. It is, however, not known whether alterations in Glu levels are accompanied by corresponding GABA alterations, nor is it known if Glu levels are affected in brain regions with known neuronal hypo-activity.
View Article and Find Full Text PDFEpidemiological studies have repeatedly shown that a significant minority of the general population have experienced hallucinations, however, a potential effect of age on the prevalence of hallucinations in the general population has never been previously examined in a specific study. The aim of the present study was thus to examine the effects of age and sensory modality on hallucination prevalence in a general population sample. A large, randomly selected and representative sample of the Norwegian population completed measures assessing different hallucination modalities (auditory, visual, olfactory, and tactile) and types (sensed presence and hypnagogic/hypnopompic hallucinations).
View Article and Find Full Text PDFThat trauma can play a significant role in the onset and maintenance of voice-hearing is one of the most striking and important developments in the recent study of psychosis. Yet the finding that trauma increases the risk for hallucination and for psychosis is quite different from the claim that trauma is necessary for either to occur. Trauma is often but not always associated with voice-hearing in populations with psychosis; voice-hearing is sometimes associated with willful training and cultivation in nonclinical populations.
View Article and Find Full Text PDFThe field of digital mental health is rapidly expanding with digital tools being used in assessment, intervention, and supporting self-help. The application of digital mental health to hallucinations is, however, at a very early stage. This report from a working group of the International Consortium on Hallucinations Research considers particular synergies between the phenomenon of hallucinations and digital tools that are being developed.
View Article and Find Full Text PDFDichotic listening (DL) taps information on the brain's language laterality, processing, and attention. Research has shown that DL responses in dyslexia deviate from the typical pattern. Here, effects of DL training and its correspondence to rapid naming (RAN) and digit span (DS) in typical children and children with dyslexia were assessed.
View Article and Find Full Text PDFAuditory verbal hallucinations complicate many psychiatric disorders. Antipsychotic medication is effective in the majority, but a significant minority experiences high burden from resistant hallucinations. Here, we aim to improve executive control, in an attempt to decrease burden from hallucinations.
View Article and Find Full Text PDFUnderstanding what happens at first onset of auditory verbal hallucinations (AVHs) is extremely important on a clinical and theoretical level. Previous studies have only focused on age with regard to first onset of AVHs. In the current epidemiological study, we examined a number of aspects relating to first onset of AVHs, such as the role of adverse life events at first onset of AVHs on symptom severity and general mental health.
View Article and Find Full Text PDFHallucinated voices are common across psychiatric and non-clinical groups. The predominant cognitive theory about the impact of voices posits that beliefs about voice power ('Omnipotence') and voice intent ('Malevolence'/'Benevolence') play a key role in determining emotional and behavioral reactions. The revised Beliefs about Voices Questionnaire (BAVQ-R) was designed to assess these constructs, together with two styles of responding (Engagement and Resistance).
View Article and Find Full Text PDFCognitive control processes play an essential role not only in controlling actions but also in guiding attentional selection processes. Interestingly, these processes are strongly affected by organizational principles of the cerebral cortex and related functional asymmetries, but the neurobiological foundations are elusive. We ask whether neurobiological mechanisms that affect functional cerebral asymmetries will also modulate effects of top-down control processes on functional cerebral asymmetries.
View Article and Find Full Text PDFSeveral studies analyzing the ontogenetic origin of cerebral lateralization provide evidences for a genetic foundation of handedness in humans that is modulated by environmental influences. Since other forms of behavioral lateralization are less investigated, it is unclear as to how far different functions display similar heritability. But deeper knowledge is necessary to understand if and how developmental coupling of different functions is based on a shared genetic background or on the impact of environmental influences.
View Article and Find Full Text PDFThe effect of aging on brain asymmetry was studied under consideration of possible confounding effects of known age-related decline in higher cognitive functioning. In a sample of 3,680 participants aged 20-79 years, laterality was assessed with a verbal, free-recall dichotic-listening paradigm with one stimulus pair presentation per trial, minimizing working-memory and cognitive-control demands during task performance. Laterality, reflected as right-ear preference for dichotic stimuli, was found to be increased in older age (above 60 years).
View Article and Find Full Text PDFThe ability to use cognitive-control functions to regulate speech perception is thought to be crucial in mastering developmental challenges, such as language acquisition during childhood or compensation for sensory decline in older age, enabling interpersonal communication and meaningful social interactions throughout the entire life span. Although previous studies indicate that cognitive control of speech perception is subject to developmental changes, its exact developmental trajectory has not been described. Thus, examining a sample of 2,988 participants (1,119 women) with an age range from 5 to 89 years, the aim of the present cross-sectional study was to examine the development of cognitive control of speech perception across the life span using age as continuous predictor.
View Article and Find Full Text PDFLeft-hemispheric language dominance has been suggested by observations in patients with brain damages as early as the 19th century, and has since been confirmed by modern behavioural and brain imaging techniques. Nevertheless, most of these studies have been conducted in small samples with predominantly Anglo-American background, thus limiting generalization and possible differences between cultural and linguistic backgrounds may be obscured. To overcome this limitation, we conducted a global dichotic listening experiment using a smartphone application for remote data collection.
View Article and Find Full Text PDFAuditory verbal hallucinations (AVHs) are a subjective experience of "hearing voices" in the absence of corresponding physical stimulation in the environment. The most remarkable feature of AVHs is their perceptual quality, that is, the experience is subjectively often as vivid as hearing an actual voice, as opposed to mental imagery or auditory memories. This has lead to propositions that dysregulation of the primary auditory cortex (PAC) is a crucial component of the neural mechanism of AVHs.
View Article and Find Full Text PDFMost psychological experimentation takes place in laboratories aiming to maximize experimental control; however, this creates artificial environments that are not representative of real-life situations. Since cognitive processes usually take place in noisy environments, they should also be tested in these contexts. The recent advent of smartphone technology provides an ideal medium for such testing.
View Article and Find Full Text PDFThe objective of the paper is to explore bottom-up auditory and top-down cognitive processing abilities as part of long-term outcome assessment of preterm birth. Fifty-five adolescents (age 13-15) born with very low birth weight (VLBW) were compared to 80 matched controls born to term, using three consonant-vowel dichotic listening (DL) instruction conditions (non-forced, forced-right and forced-left). DL scores were correlated with cortical gray matter thickness derived from T1-weighted structural MRI volumes using FreeSurfer to examine group differences also in the neural correlates of higher cognitive processes.
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