Auditory Hallucinatory Experiences Research Articles

The dimensionality of perceptual anomalies and their relationships with bullying victimization among Chinese adolescents: From a network perspective

Anomalous perceptual experiences in adolescents are common and may predict future psychotic disorders and other psychopathologies. However, the underlying structure and their specific relationships with bullying victimizations, a typical stressor for adolescents, remain unclear. Therefore, the current study aimed to clarify the structure of perceptual anomalies as assessed by the Cardiff Anomalous Perceptions Scale (CAPS) using exploratory graph analysis (EGA), a new factor retention method based on network psychometrics. The second aim was to explore whether specific dimensions of perceptual anomalies are particularly associated with certain forms of bullying victimization. Data from a validated sample of 1199 Chinese adolescents (56.0 % females, age range: 14–20) on perceptual anomalies and bullying victimizations were analyzed using network approaches, including EGA and mixed graphical modeling (mgm). Results showed that each anomalous perception was experienced by 13.8–50.3 % of the participants. EGA identified four dimensions: aberrant bodily perceptions, altered daily experiences, chemosensation (i.e., abnormal gustatory and olfactory experiences), and clinical psychosis (i.e., visual and auditory hallucinatory experiences). Among them, the altered daily experiences dimension possessed the highest centrality. Physical bullying and cyberbullying were directly and positively linked to two of the aberrant bodily experiences. Bootstrap analyses suggest that the results are reliable. The current findings support the existence of multiple contributive factors to perceptual anomalies and underscore the importance of bullying prevention in reducing mental health risks for adolescents, particularly the risk of psychosis.

Can't get you out of my head: Persistence and remission of psychotic experiences in adolescents and its association with self-injury and suicide attempts

BackgroundPersistent psychotic experiences (PEs) may increase risk for mental disorders, non-suicidal self-injury (NSSI), and suicide attempts, relative to PEs that are more transient and remitting in nature. Most investigations of PE persistence have incorporated only two waves of data, and have not investigated the persistence of different PE subtypes and their association with future NSSI and suicide attempts. This study aimed to investigate the association between PE persistence, NSSI, and suicide attempts using three waves of prospective data. A secondary aim was to investigate potential reverse pathways where self-injurious behaviour (and its persistence) instead precedes subsequent PE occurrence. MethodParticipants were 1100 adolescents (12–17 years) from an Australian prospective cohort study; with three time points over two years. The Self-Harm Behaviour Questionnaire was used to assess NSSI and suicide attempts. Four PE subtypes (auditory hallucinatory experiences [HEs], and three delusional experiences) were assessed using the Diagnostic Interview Schedule for Children. Logistic regression analyses were conducted where PEs was grouped into five categories according to their persistence across the three waves of data. Analyses were adjusted for sociodemographics and substance use. ResultsOverall, persistence of PEs (with endorsement of PE across two or three waves) was associated with the highest risk of incident NSSI and suicide attempts at 1- and 2-year follow-up (OR range: 2.57–12.25), whereas remitted PEs (with endorsement of PE at baseline only) were not associated with increased risk of future NSSI or suicide attempts. This pattern of association was evident for auditory HEs but not for most other PE subtypes; although some estimates had wide confidence intervals. There was no support for reverse temporality. ConclusionOur findings support and extend the two-wave cohort literature demonstrating that PEs which persist over time are more robust predictors of future NSSI and suicidal behaviour. Auditory HEs that are persisting in nature are an important but under-recognised risk factor for NSSI and suicide attempts during adolescence, and current findings should inform clinical guidelines into the predictors of self-harm and suicide risk at this life stage.

Urban upbringing and psychotic experiences in the United States: A racial and geographic comparison

Urban upbringing has been associated with greater risk for psychotic experiences, though research is needed to confirm whether this is true in the U.S., and whether the association depends on race, type of experience, and region of the country. We analyzed data from the National Comorbidity Survey Replication (White respondents only) and the National Survey of American Life (Black respondents). Multivariable logistic regression models found that urban upbringing was not significantly associated with lifetime psychotic experiences for Whites, but was significantly associated with lower odds for Blacks, adjusting for socio-demographic covariates and common mental disorders. Rural upbringing was associated with greater odds of lifetime auditory hallucinatory experiences for Blacks. Exploratory analyses suggested growing up in a large city or ‘other’ environment were associated with greater odds of lifetime psychotic experiences among Whites currently residing in the Northeast, but lower odds among Whites residing in the South. For Blacks currently residing in the West, rural upbringing was associated with significantly greater odds of lifetime psychotic experiences when compared with growing up in a large city. White and Blacks may have different lived experiences in urban and rural settings, calling for more race- and location- specific research to explain these diverging patterns.

Mediators of the association between psychotic experiences and future non-suicidal self-injury and suicide attempts: results from a three-wave, prospective adolescent cohort study.

Psychotic experiences (PEs) are robustly associated with subsequent non-suicidal self-injury (NSSI) and suicide attempts, but questions remain as to the temporal relation and underlying cause of this association. Most investigations have incorporated only two waves of data, and no study has comprehensively investigated mediating pathways. This study aimed to investigate both the PE-NSSI and PE-suicide attempt association, and their relevant mediators, across three waves of prospective data. Participants were from an Australian prospective longitudinal cohort of 1100 adolescents (12-17years); data were collected at three time points over 2 years. NSSI and suicide attempts were measured using the Self-Harm Behaviour Questionnaire. Items from the Diagnostic Interview Schedule for Children were used to assess four PE subtypes (auditory hallucinatory experiences [HEs] and three delusional experiences). Potential mediators of interest included: psychological distress, self-reported mental disorders, self-esteem, recent traumatic life events (e.g. bullying, sexual assault), emotion regulation, and impulsivity/other personality traits. Analyses were adjusted for sociodemographics and substance use. Auditory HEs were indirectly associated with future NSSI and suicide attempts via recent traumatic life events, high psychological distress, and low self-esteem, across three waves of data. Other PE subtypes were generally not associated with incident NSSI/suicide attempts at 1- and 2-year follow-up, either directly or indirectly. These findings highlight the importance of screening for auditory HEs when assessing a young person's self-harm/suicide risk. Clinical assessment would be further enhanced by a comprehensive review of recent interpersonal traumatic events, as well as levels of self-esteem and distress.

The effect of rumination and distraction on auditory hallucinatory experiences: An analogue experimental study

Background and objectivesThe cognitive model of voices suggests that negative appraisals of hallucinatory experiences result in responses, such as rumination, which maintain voice-hearing. Our principal aim was to investigate the effect of rumination on the frequency of voice-hearing. MethodsA two-group randomised experimental design was employed using a non-clinical sample. A total of 106 participants completed baseline measures of trait rumination, hallucination-proneness, mood and state negative affect, and were presented with a voice-hearing paradigm. False feedback designed to cause a negative interpretation of auditory intrusions was provided and participants were randomly allocated to either a distraction or rumination condition. Participants performed the auditory task for a second time, and the total number of false alarms and distress scores were compared between groups. ResultsA Mann-Whitney U test revealed that the manipulation of rumination was successful (p = 0.007). We did not detect a statistically significant difference between the distraction and rumination groups for total false alarms (p = 0.282) or distress (p = 0.387) scores. LimitationsFindings largely relate to a female undergraduate psychology sample. ConclusionResults of this non-clinical study do not support the hypothesis that rumination leads to an increase in the frequency of voice-hearing on a laboratory task.

Explications cognitives des hallucinations acoustico-verbales dans la schizophrénie : un article de synthèse de la littérature scientifique

AimsOur article consists in both analysis and synthesis of contemporary cognitive models of auditory verbal hallucinations (AVHs) in schizophrenia. Our work is based on the analysis of the scientific literature including original articles, literature reviews as well as meta-analysis. MethodologyIn order to identify the most pertinent studies in the electronic search, the three following databases were systematically searched: PubMed, PsycINFO and MEDLINE. For both the analysis and synthesis we selected original articles, literature reviews as well as meta-analysis referring to any cognitive explanation of the auditory hallucinatory experience in schizophrenia. A cognitive model of auditory hallucinations refers to any incorporation of cognitive frameworks and explanations in one's conceptualization of the hallucinatory phenomenon in schizophrenia. We also focused our work on past conceptualization of auditory hallucinations in order to explain the development and the contribution of current cognitive models in the understanding of the onset and the maintaining of AVHs. After a brief review of clinical characteristics and historical conceptualization of auditory verbal hallucinations, contemporary explanations were presented in the area of schizophrenia. These explanations referred to researches into cognitive psychopathology including metacognitive as well as neuroimaging studies. ResultsThe examination of scientific literature highlighted the complexity of AVHs through multifactorial explanations here mostly explained by cognitive and metacognitive deficits. We synthesized former conceptualizations of AVHs, which were sustained on mechanistic or sensory explanations. Esquirol, Baillarger and Briere de Boismont were the first as conceiving AVHs as a perception disorder and introduced the idea that auditory hallucinations resulted from a failure to control one's memories/fantasies. Later, Broca and Wernicke discovered auditory areas in the human brain implicated in language comprehension and production. AVHs began to be conceptualized by the scientific world as being mechanistically brain-related. Sigmund Freud was among the first to study the meaning of AVHs, a domain still being investigated by todays cognitive sciences. More recently, neuroimaging studies allowed the validation of these sensory explanations in considering the onset of AVHs through the deficit of cortical and subcortical areas implicated in the process of languages (e.g. Broca and Wernicke areas) and emotions (e.g. limbic system, amygdala, hippocampus). At a more mechanistic level, contemporary cognitive models of AVHs explained AVHs as an intrusive verbal representation into the awareness which is non-inhibited (i.e. deficit in intentional inhibition) and also non-recognized as one's own experience (i.e. deficit in source monitoring, planning and metacognition), or even attributed to an external source (attribution bias). In terms of inhibitory control, inhibition is a basic cognitive mechanism defined as a collection of processes that allows the suppression of previously activated cognitive contents and the clearing of irrelevant actions or attention from consciousness. Intentional inhibition is effortful and occurs when an individual deliberately suppresses the activation of an item after deciding it is irrelevant. Theoretical support for the suggestion that an inhibitory failure is involved in AVHs in schizophrenia arises from studies that have shown that a failure in inhibition results in intrusive thoughts from long-term memory. Recent findings also found that individuals with AVHs in schizophrenia demonstrated an impaired source monitoring. In episodic memory research, a distinction was made between content (an event) and context (e.g. source or temporal characteristics of an event) information. The context of memories provides cues that allow an individual to differentiate one memory from other memories. AVHs are conceptualized as a failure to access the contextual cues that would allow voice-hearer to form an intact representation of events in memories. Regarding planning, AVHs refer to the intrusion of unwanted memories into the inner speech that are not recognized from one's own representation. Previous cognitive theories highlighted the important role played by metacognitive skills and belief (i.e. thinking about one's thinking) in the explanation of AVHs. Finally, the external attribution bias was extensively studied over the last three decades and refers to the tendency to attribute negative events (situational or cognitive) to an external source. In this framework, AVHs refer to intrusive thoughts externally attributed to a voice. ConclusionFor more than one century, scientific discoveries in (bio)medical science have allowed the validation of former sensory and mechanistic explanations of AVHs. Nevertheless, many explanatory models account for the way AVHs are maintained (source monitoring, deficit in planning, externalizing bias), while they scarcely expose how they are triggered (intrusive thoughts, deficit in inhibition). The relation between AVHs and intrusive thoughts still remain unclear, and further studies are needed for the understanding of a potential causal relationship.

Investigating the role of hallucinatory experiences in the transition from suicidal thoughts to attempts.

Psychotic experiences, including auditory hallucinatory experiences (HEs), are strongly associated with both suicidal thoughts and behaviour. This study examined their role in the ideation-to-attempt transition in adolescents, including their direct and indirect effect via potential mediators. Participants were from an Australian prospective longitudinal cohort of 1669 adolescents (12-17years); of which a subsample endorsing baseline suicidal ideation (n=216) was the focus of most analyses. Suicidal thoughts and behaviours were measured using the Self-Harm Behaviour Questionnaire. The Diagnostic Interview Schedule for Children was used to assess auditory HEs. Potential mediators of interest were psychological distress and Interpersonal Theory of Suicide (IPTS) constructs. Among adolescents reporting suicidal ideation at baseline (n=216), 6.5% had attempted suicide during follow-up. The size of auditory HEs' univariate effect suggests a possible strong relationship with increased risk of incident suicide attempts (OR=2.40; 95%CI=0.76-7.56); however, there was inadequate statistical power to produce a precise estimate. When HEs were accompanied by distress there was a nine-fold increased risk of acting on suicidal thoughts. Distress was independently associated with risk of attempt transition (OR=4.09), whereas IPTS constructs were poor explanatory variables in most models. Adolescents with psychological distress and auditory HEs are at high risk of incident suicide attempts. Further investigations on the role of negative/distressing content of hallucinations in the ideation-to-attempt transition are warranted.

Prevalence and correlates of psychotic experiences in a nationally representative sample of Australian adolescents.

Despite growing literature on psychotic experiences, no nationally representative study has reported on the prevalence of both hallucinatory experiences and delusional experiences in Australian adolescents. Also, while many studies have examined the association between psychotic experiences and certain demographic and clinical correlates, there are more variables of interest to be investigated, including disordered eating behaviour and hours of sleep. The aims of this study were to examine (1) the prevalence of hallucinatory experiences and delusional experiences in Australian adolescents, and (2) the associations between different types of psychotic experiences with a broad range of demographic, clinical, and psychosocial variables. A random sample of Australian adolescents aged 14- to 17-year-olds were recruited in 2013-2014 as part of the Young Minds Matter Survey. Participants completed self-report questions regarding five different psychotic experience types (auditory and visual hallucinatory experiences, and thoughts read, special messages, spied upon) experienced in the past 12 months. Using logistic regression analyses, we investigated associations between psychotic experiences and demographic, clinical, and psychosocial factors. The 12-month prevalence ranged from 3.3% (95% confidence interval = [2.6, 4.3]) for special messages to 14.0% (95% confidence interval = [12.3, 15.8]) for auditory hallucinatory experiences. At the bivariate level, each psychotic experience subtype was associated with increased likelihood of major depression, being bullied, psychological distress, low self-esteem, mental health service use and insufficient sleep (<8 hours per night). Multivariate analyses revealed both auditory and visual hallucinatory experiences were associated with an increased likelihood of four of these variables (depression, being bullied, service use, insufficient sleep), whereas associations with delusional experiences were inconsistent. Hallucinatory and delusional experiences are common in Australian adolescents. Hallucinatory experiences, rather than delusional experiences, may be more clinically relevant in this demographic. When psychotic experiences are endorsed by adolescents, further assessment is indicated so as to ascertain more detail on the phenomenology of the experiences to better understand their clinical relevance.

Attributional biases in psychiatric patients, a religious, and a control group in the assessment of a hallucinatory experience: The “White Christmas Test”

The aim of this study was to evaluate the auditory hallucinatory experience in a clinical sample of patients with psychiatric symptoms (e.g. Schizophrenia), a religious group (e.g. Christians) and a “control” group (with no mental disorder and non-religious). The sample consisted of individuals of both sexes. The patient sample was recruited in two psychiatric hospitals of Buenos Aires City, the religious from an evangelical cult, and people with no religious beliefs or previous psychiatric symptoms (control group). The Hallucinatory Experiences Questionnaire and the Oxford-Liverpool Inventory Feelings and Experiences were the measurement tools used. The White Christmas Test was also administered in order to assess the degree of vivid imagery hearing based on a version of signal detection paradigm in which the subjects think that they hear a song in the background of white noise. The results showed that patients showed greater attributional bias (compared with evangelicals and the control group), but the religious group also tended to show greater bias (although less) than the control group. In addition, patients tended to show greater schizotypal and hallucinatory experiences compared with the evangelicals and the control group, but surprisingly, the control group showed higher negative schizotypy than the religious group, which indicates that religious practices could help reduce the negative effects of schizotypy.

Auditory feature perception and auditory hallucinatory experiences in schizophrenia spectrum disorder.

Schizophrenia spectrum disorder (SZ) is associated with deficits in auditory perception as well as auditory verbal hallucinations (AVH). However, the relationship between auditory feature perception and auditory verbal hallucinations (AVH), one of the most commonly occurring symptoms in psychosis, has not been well characterized. This study evaluated perception of a broad range of auditory features in SZ and determined whether current AVHs relate to auditory feature perception. Auditory perception, including frequency, intensity, duration, pulse-train and temporal order discrimination, as well as an embedded tone task, was assessed in both AVH (n=20) and non-AVH (n=24) SZ individuals and in healthy controls (n=29) with the Test of Basic Auditory Capabilities (TBAC). The Hamilton Program for Schizophrenia Voices Questionnaire (HPSVQ) was used to assess the experience of auditory hallucinations in patients with SZ. Findings suggest that compared to controls, the SZ group had greater deficits on an array of auditory features, with non-AVH SZ individuals showing the most severe degree of abnormality. IQ and measures of cognitive processing were positively associated with performance on the TBAC for all SZ individuals, but not with the HPSVQ scores. These findings indicate that persons with SZ demonstrate impaired auditory perception for a broad range of features. It does not appear that impaired auditory perception is associated with recent auditory verbal hallucinations, but instead associated with the degree of intellectual impairment in SZ.

Psychotic experiences and disability: Findings from the Collaborative Psychiatric Epidemiology Surveys

Psychotic experiences are associated with a number of poor clinical outcomes, including multimorbid psychopathology, suicidal behavior, and poor treatment response. We wished to investigate the relationship between psychotic experiences and disability, including the following domains: cognition, mobility, self-care, social interaction, role functioning, and days out of role. We used three nationally representative and racially/ethnically diverse samples of the general US adult population: the National Comorbidity Survey Replication (NCS-R), the National Latino and Asian American Survey (NLAAS), and the National Survey of American Life (NSAL). Multi-variable logistic regression analyses were used to assess the associations between lifetime psychotic experiences (visual and auditory hallucinatory experiences and delusional ideation; WHO Composite International Diagnostic Interview psychosis screen) and 30-day impairments in functioning across disability domains (using the WHO Disability Assessment Schedule II). In all three samples, models were adjusted for socio-demographics and co-occurring psychiatric disorders. In the NCS-R, models were also adjusted for chronic health conditions. Across all three studies, our adjusted models showed that people with disability had anywhere from about 1.5 to over 3 times the odds of reporting lifetime psychotic experiences, depending on the domain. This was true for each disability domain, except self-care in the NLAAS and in the NSAL. Psychotic experiences are markers of risk for disability across a wide range of domains. This may explain the elevated rates of service utilization among individuals who report psychotic experiences and supports the need to assess for and respond to psychotic experiences even in the absence of psychotic disorder.

Sesgo atribucional en pacientes psiquiátricos, religiosos y un grupo control en el juicio de la experiencia alucinatoria: la tarea del White Christmas test

The aim of this study was to evaluate the auditory hallucinatory experience in a clinical sample of patients with psychiatric symptoms (e.g. Schizophrenia), a religious group (eg. Christians) and a “control” group (with no mental disorder and non-religious). The sample consisted of individuals of both sexes. The patient sample was recruited in two psychiatric hospitals of Buenos Aires City, the religious from an evangelical cult, and people with no religious beliefs or previous psychiatric symptoms (control group). The Hallucinatory Experiences Questionnaire and the Oxford-Liverpool Inventory Feelings and Experiences were the measurement tools used. The White Christmas Test was also administered in order to assess the degree of vivid imagery hearing based on a version of signal detection paradigm in which the subjects think that they hear a song in the background of white noise. The results showed that patients showed greater attributional bias (compared with evangelicals and the control group), but the religious group also tended to show greater bias (although less) than the control group. In addition, patients tended to show greater schizotypal and hallucinatory experiences compared with the evangelicals and the control group, but surprisingly, the control group showed higher negative schizotypy than the religious group, which indicates that religious practices could help reduce the negative effects of schizotypy.

Acute Methiopropamine Intoxication After “Synthacaine” Consumption

Use of methiopropamine (MPA), a synthetic metamfetamine analog, has been detected since 2011 in Europe, but there is limited information on its acute toxicity. A 30-year-old man was admitted to the emergency department in a confused state, with paranoid delusion, auditory and visual hallucinatory experiences, and incoherent speech following the use of "synthacaine" (a slang term derived from "synthetic" and "cocaine"). Toxicological screening for pharmaceuticals and drugs of abuse by liquid chromatography-diode-array detector, gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry (LC-MS-MS) detected MPA, which was subsequently quantified by a specific LC-MS-MS method. Of note, 13 h after presentation to the emergency department, the plasma concentration of MPA was 14 ng/mL. This case report confirms the toxicity of MPA and the need for toxicological analysis to confirm the substance actually ingested by users of new psychoactive substances.

It's a Mad, Mad, Mad, Mad World

Worldwide, how common are psychotic experiences (PEs)? To assess the frequency of six discrete PEs in 31,261 community-living adults in 18 countries in North and South America, Africa, the Middle East, Asia, Europe, and the South Pacific, trained lay interviewers used a validated, structured clinical interview. People with evidence of a psychotic disorder were excluded. Assessed PEs included auditory or visual hallucinatory experiences (HEs) …

Chapter 24 - Auditory hallucinations

Auditory hallucinations constitute a phenomenologically rich group of endogenously mediated percepts which are associated with psychiatric, neurologic, otologic, and other medical conditions, but which are also experienced by 10-15% of all healthy individuals in the general population. The group of phenomena is probably best known for its verbal auditory subtype, but it also includes musical hallucinations, echo of reading, exploding-head syndrome, and many other types. The subgroup of verbal auditory hallucinations has been studied extensively with the aid of neuroimaging techniques, and from those studies emerges an outline of a functional as well as a structural network of widely distributed brain areas involved in their mediation. The present chapter provides an overview of the various types of auditory hallucination described in the literature, summarizes our current knowledge of the auditory networks involved in their mediation, and draws on ideas from the philosophy of science and network science to reconceptualize the auditory hallucinatory experience, and point out directions for future research into its neurobiologic substrates. In addition, it provides an overview of known associations with various clinical conditions and of the existing evidence for pharmacologic and non-pharmacologic treatments.

Perceived discrimination and psychotic experiences across multiple ethnic groups in the United States

ObjectiveThe objective of this study was to examine the relationship between perceived discrimination and psychotic experiences (PE) using validated measures of discrimination and a racially/ethnically diverse population-level sample. MethodsData were drawn from two population-level surveys (The National Latino and Asian American Survey and The National Survey of American Life), which were analyzed together using survey weights and stratification variables. The analytic sample (N=8990) consisted of Latino, Asian, African–American, and Afro-Caribbean adults living in the United States. Separate unadjusted and adjusted multivariable logistic regression models were used, first to examine the crude bivariate relationship between perceived discrimination and PE, and second to examine the relationship adjusting for demographic variables. Adjusted logistic regression models were also used to examine the relationships between perceived discrimination and specific sub-types of PE (auditory and visual hallucinatory experiences, and delusional ideation). ResultsWhen compared to individuals who did not report any discrimination, those who reported the highest levels of discrimination were significantly more likely to report both 12-month PE (Adjusted OR=4.590, p<0.001) and lifetime PE (adjusted OR=4.270, p<0.001). This held true for visual hallucinatory experiences (adjusted OR=3.745, p<0.001), auditory hallucinatory experiences (adjusted OR=5.649, p<0.001), and delusional ideation (adjusted OR=7.208, p<0.001). ConclusionPerceived discrimination is associated with the increased probability of reporting psychotic experiences in a linear Fashion in the US general population.

Persistent auditory hallucinations and treatment challenges.

Despite improved neurotransmitter identification and emergence of novel antipsychotics, treatment of auditory hallucinatory experiences is frustrating. Interest has developed in non-pharmacological approaches to this problem – these do not eliminate the voices but reduce the distress associated with the experience.

Effect of High or Low Imagery on Auditory Hallucinatory Content in Individuals Scoring High in Schizotypy

The present study examined the occurrence, and content, of auditory hallucinatory experiences in non-clinical participants scoring high or low in schizotypy. Participants listened to 10 one-minute recordings of white noise, some of which contained embedded high or low imagery words, and were asked to record any words that they heard. Results showed that high scorers on the unusual experiences scale of the Oxford-Liverpool Inventory of Feelings and Experiences showed a bias toward making hallucinatory reports of a low imagery type than of a high imagery type, but there were no significant differences for low UE scorers. Low scorers in impulsive nonconformity made more low imagery hallucinatory reports than high imagery reports. The results suggest a bias toward more hallucinatory reports of low imagery words.

P-1260 - Neurochemical modulation of auditory processing in healthy controls stratified for low and high auditory hallucinatory experiences

Contributing to poor global functioning, auditory hallucinations (AH) also interfere with elementary cognitive processes, including auditory discrimination. This is evidenced in schizophrenic (SZ) hallucinators (vs. non-hallucinators) by a greater reduction of the MMN, an auditory event-related brain potential (ERP) generated in part by NMDA receptor activity and normalized with nicotinic (nACh) agonist treatment. To increase our understanding of NMDA-nACh interactions with auditory processing, using healthy young adults varying in their degree of experience with AH, thereby reducing the confounding influence of illness chronicity and medication associated with the study of SZ patients. To investigate MMN differences between low and high AH subjects during separate and combined administration of ketamine, an NMDA antagonist, and nicotine, an nACh agonist. In 40 healthy controls, all rated for AH with the Bell Object Relations and Reality Testing Inventory, MMN to frequency deviants was assessed in a randomized, placebo-controlled crossover design involving the separate and combined administration of a intravenous sub-psychotomimetic dose of ketamine (0.04 mg/kg) and a dose of nicotine gum (4 mg). In high AH subjects, ketamine reduced MMN, with the resulting amplitude being smaller than that of low AH subjects. This ketamine-induced MMN reduction was evident only with placebo gum; furthermore combined nicotine-ketamine treatment acted to increase MMN in high scorers. AH in otherwise healthy individuals is associated with heightened sensitivity to NMDA receptor blockade, the effects of which are moderated by nicotinic neurotransmission. Both neurotransmitters may interact to moderate auditory processing and AH in SZ.

Effect of a context of concrete and abstract words on hallucinatory content in individuals scoring high in schizotypy

The present study examined the occurrence and content of auditory hallucinatory experiences in 41 non-clinical participants scoring high or low on the Oxford-Liverpool Inventory of Feelings and Experiences (brief version; OLIFE-B) measure of schizotypy. Participants listened to 10 1-min recordings of white noise, some of which contained embedded concrete or abstract words, and were asked to record the words that they had heard. High scorers on the unusual experiences (UE) scale of the OLIFE-B reported hearing more words, not actually present, relative to low scorers on that measure. In addition, high UE scorers showed a bias toward making hallucinatory reports of an abstract type over a concrete type. These results suggest a bias toward more auditory hallucinatory reports in high scorers in schizotypy, and particularly to those of an abstract type.