What self-generated speech is externally misattributed in psychosis? Testing three cognitive models in a first-episode sample

Understanding source monitoring subtypes and their relation to psychosis: a systematic review and meta-analysis

AIMS

Source monitoring (SM) is the metacognitive ability to determine the origin of one's experiences. SM is altered in primary psychiatric psychosis, although relationships between SM subtypes, other cognitive domains and symptoms are unclear. Our aims were to synthesize evidence comparing psychosis -with and without hallucinations- and healthy controls classifying SM subtypes by source discrimination (internal/external/reality monitoring) and stimulus modality (visual/auditory/imagined/performed).

METHODS

This systematic review adopted Preferred Reporting Items for Systematic Reviews and Meta-Analyses, Meta-analyses Of Observational Studies in Epidemiology and Population, Intervention, Comparison and Outcomes guidelines. Core demographical and clinical parameters were extracted. Newcastle-Ottawa Scale was used as quality check. SM differences between (i) psychosis patients versus healthy controls and (ii) patients with versus without hallucinations were investigated via random-effect model meta-analysis. The primary effect size measure was standardized mean difference (SMD) in each SM subtype performance (error or accuracy). Heterogeneity, publication biases and meta-regressions were assessed.

RESULTS

Five thousand two hundred and fifty-six records were screened to finally include 44 studies (1566 patients, 1175 controls). Mean Newcastle-Ottawa score was 7.41 out of 9. Few studies measured SM associations with cognition (n = 9) and symptoms (n = 19), with heterogeneous findings. SM performance across all measures was reduced in psychosis versus healthy controls (SMD = 0.458). Internal SM (SMD: errors = 0.513; accuracy = 0.733) and imagined stimuli (SMD: errors = 0.688; accuracy = 0.978) were specifically impaired. Patients with versus without hallucinations showed SM deficits only for externalizing (SMD = 0.410) and imagined/auditory (SMD = 0.498/0.277) errors.

CONCLUSION

The proposed classifications highlight specific SM deficits for internal/imagined stimuli in psychosis, providing evidence-based indications to design and interpret future studies.

Prevalence and types of childhood trauma in first episode psychosis patients. Relation with clinical onset variables

OBJECTIVE

To study the prevalence and the type of childhood trauma (CT) in a first-episode psychosis (FEP) cohort and in a healthy control (HC) sample. To study which clinical and sociodemographic variables in the onset of the FEP are related to having suffered some traumatic experience in childhood.

METHOD

100 FEP patients and 94 HC participated in the study. The Childhood Traumatic Questionnaire (CTQ) was used to evaluate CT. The Positive and Negative Syndrome Scale (PANSS), the Personal and Social Performance (PSP), the Suicide Risk Scale of Plutchik (SRSP), and the Perceived Stress Scale (PSS) were also administered.

RESULTS

61% of FEP patients and 17% of HC reported having experienced some kind of CT. FEP showed more CT than controls in all subscales, except in sexual abuse. The most frequent CT was emotional abuse. For the FEP group, younger age, more years of education, have a first-degree family history, more positive and negative symptoms, more perceived stress and more personal and social functioning were the variables more influenced by having suffered some kind of CT.

CONCLUSIONS

There is a high prevalence of CT in FEP patients. Having a first-degree family history of mental illness, more positive symptoms, and more perception of stress at the time of hospital admission were related to having suffered CT. More research is needed to find out the best way to detect CT and its role in psychosis to be able to implement interventions to improve the evolution of these patients.

Childhood trauma and cognitive biases associated with psychosis: A systematic review and meta-analysis

Childhood trauma is associated with an increased risk of psychosis, but the mechanisms that mediate this relationship are unknown. Exposure to trauma has been hypothesised to lead to cognitive biases that might have causal effects on psychotic symptoms. The literature on whether childhood trauma is associated with psychosis-related cognitive biases has not been comprehensively reviewed. A systematic review and meta-analysis or narrative synthesis of studies examining the association between childhood trauma and the following biases: external locus of control (LOC), external attribution, probabilistic reasoning, source monitoring, top-down processing, and bias against disconfirmatory evidence. Studies were assessed for quality, and sources of heterogeneity were explored. We included 25 studies from 3,465 studies identified. Individuals exposed to childhood trauma reported a more external LOC (14 studies: SMD Median = 0.40, Interquartile range 0.07 to 0.52), consistent with a narrative synthesis of 11 other studies of LOC. There was substantial heterogeneity in the meta-analysis (I2 = 93%) not explained by study characteristics examined. Narrative syntheses for other biases showed weaker, or no evidence of association with trauma. The quality of included studies was generally low. Our review provides some evidence of an association between childhood trauma and a more external LOC, but not with the other biases examined. The low quality and paucity of studies for most of the cognitive biases examined highlights the need for more rigorous studies to determine which biases occur after trauma, and whether they mediate an effect of childhood trauma on psychosis.

Psychological processes mediating the association between developmental trauma and specific psychotic symptoms in adults: a systematic review and meta-analysis

Experiencing psychological trauma during childhood and/or adolescence is associated with an increased risk of psychosis in adulthood. However, we lack a clear knowledge of how developmental trauma induces vulnerability to psychotic symptoms. Understanding the psychological processes involved in this association is crucial to the development of preventive interventions and improved treatments. We sought to systematically review the literature and combine findings using meta-analytic techniques to establish the potential roles of psychological processes in the associations between developmental trauma and specific psychotic experiences (i.e., hallucinations, delusions and paranoia). Twenty-two studies met our inclusion criteria. We found mediating roles of dissociation, emotional dysregulation and post-traumatic stress disorder (PTSD) symptoms (avoidance, numbing and hyperarousal) between developmental trauma and hallucinations. There was also evidence of a mediating role of negative schemata, i.e. mental constructs of meanings, between developmental trauma and delusions as well as paranoia. Many studies to date have been of poor quality, and the field is limited by mostly cross-sectional research. Our findings suggest that there may be distinct psy-chological pathways from developmental trauma to psychotic phenomena in adulthood. Clinicians should carefully ask people with psychosis about their history of developmental trauma, and screen patients with such a history for dissociation, emotional dysregulation and PTSD symptoms. Well conducted research with prospective designs, including neurocognitive assessment, is required in order to fully understand the biopsychosocial mechanisms underlying the association between developmental trauma and psychosis.

Types, prevalence and gender differences of childhood trauma in first-episode psychosis. What is the evidence that childhood trauma is related to symptoms and functional outcomes in first episode psychosis? A systematic review

This paper reviews and discusses the literature on childhood trauma (CT) in people with first-episode psychosis (FEP). The aim is to update the knowledge on the prevalence and the types of CT suffered by FEP people, to compare them with other samples, to study the impact of gender, and to examine the relationship between CT and symptoms and functional outcomes. We conducted a literature search (1995-2019), to identify reported data on any topic related to CT in FEP samples. The following terms were used in the search: CT or sexual abuse or physical abuse or neglect, and first-episode psychosis. We found 493 studies, of which 68 were included in the review. FEP presented a higher prevalence of CT than controls. Women suffer more sexual abuse. The effect of CT on the severity, the prognosis and the evolution of FEP is unclear. FEP have a high prevalence of CT. Its relationship with symptoms and functional outcomes indicates its importance within treatment. This suggests the importance of creating and implementing specific interventions and personalized therapies addressed to work through their past traumatic experiences to improve their quality of live and their prognosis.

Childhood Trauma Is Associated With Severity of Hallucinations and Delusions in Psychotic Disorders: A Systematic Review and Meta-Analysis

Introduction

Childhood trauma is a risk factor for the development of psychosis. Furthermore, a number of theories propose specific mechanisms by which childhood trauma may contribute to more severe positive and negative psychotic symptoms, some of which are supported empirically. The robustness of this empirical evidence is unclear due to mixed results and methodological limitations of individual studies. A systematic review and meta-analysis of the evidence for associations between childhood trauma and severity of hallucinations, delusions, and negative psychotic symptoms in clinical populations with a diagnosed psychotic disorder is needed.

Method

A systematic search was conducted. Reference lists of relevant review articles were hand-searched, and authors contacted for data and additional unpublished studies. Study reporting bias and quality was assessed.

Results

In total, 6667 studies were identified and of these 41 studies met inclusion criteria. Of these, 29 studies (4680 participants) were meta-analyzed. Among individuals with psychosis, childhood trauma was significantly correlated with severity of hallucinations (r = .199, P < .001) and delusions (r = .172, P < .001) but contrary to our hypothesis, not correlated with severity of negative symptoms (r = .049, P = .095). Severity of childhood neglect was correlated with negative symptoms (r = .142, P = .005).

Conclusion

The results lend support for cognitive and biological theories that traumas in childhood may lead to hallucinations and delusions within psychotic disorders and have important implications for clinical practice.

Attentional avoidance increases voice hearing in an analogue task in people with psychosis: An experimental study

Cognitive models of psychosis suggest that unhelpful ways of responding to experiences can maintain such experiences and the associated distress. The response styles of attentional avoidance and attentional focusing were manipulated in an analogue voice-hearing task. Predictions were that both would increase detection of words in response to an ambiguous audio-recording but that attentional avoidance would lead to a greater increase than focusing. We also predicted that there would be a greater increase in anxiety and distress in the avoidance group. Predictions were tested in a sample of 44 participants with a diagnosis of schizophrenia. Participants were randomly assigned to either attentional avoidance or focusing while listening to an ambiguous auditory task. Number of words identified and anxiety and distress were recorded. As predicted, there was an increase in the number of words identified in both groups; however, this increase was greater in the avoidance group. The prediction that there would also be an increase in distress that would be greater in the avoidance group was not supported. It is possible that emotional reactions relate more closely to appraisals of the voice. The results suggest that avoidance of experiences is particularly counterproductive and can result in greater detection of experiences.

Dissociation mediates the relationship between peer victimization and hallucinatory experiences among early adolescents

Peer victimization increases the risk of experiencing psychotic symptoms among clinical and general populations, but the mechanism underlying this association remains unclear. Dissociation, which is related to peer victimization and hallucinatory experiences, has been demonstrated as a significant mediator in the relation between childhood victimization and hallucinatory experience among adult patients with psychosis. However, no studies have examined the mediating effect of dissociation in a general early adolescent population. We examined whether dissociation mediates the relationship between peer victimization and hallucinatory experiences among 10-year-old adolescents using a population-based cross-sectional survey of early adolescents and their main parent (Tokyo Early Adolescence Survey; N = 4478). We examined the mediating effect of dissociation, as well as external locus of control and depressive symptoms, on the relationship between peer victimization and hallucinatory experiences using path analysis. The model assuming mediation effects indicated good model fit (comparative fit index = .999; root mean square error of approximation = .015). The mediation effect between peer victimization and hallucination via dissociation (standardized indirect effect = .038, p < .001) was statistically significant, whereas the mediation effects of depressive symptoms (standardized indirect effect = -.0066, p = 0.318) and external locus of control (standardized indirect effect = .0024, p = 0.321) were not significant. These results suggest that dissociation is a mediator in the relation between peer victimization and hallucinatory experiences in early adolescence. For appropriate intervention strategies, assessing dissociation and peer victimization as they affect hallucinatory experiences is necessary.

The effect of auditory verbal imagery on signal detection in hallucination-prone individuals

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Investigated relation between hallucinations, mental imagery and signal detection.

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Individuals prone to hallucinations showed a lower SDT response bias with imagery.

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Finding held for both instructed and self-reported use of auditory verbal imagery.

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Atypical auditory imagery may lead to the generation of auditory hallucinations.

Cognitive models have suggested that auditory hallucinations occur when internal mental events, such as inner speech or auditory verbal imagery (AVI), are misattributed to an external source. This has been supported by numerous studies indicating that individuals who experience hallucinations tend to perform in a biased manner on tasks that require them to distinguish self-generated from non-self-generated perceptions. However, these tasks have typically been of limited relevance to inner speech models of hallucinations, because they have not manipulated the AVI that participants used during the task. Here, a new paradigm was employed to investigate the interaction between imagery and perception, in which a healthy, non-clinical sample of participants were instructed to use AVI whilst completing an auditory signal detection task. It was hypothesized that AVI-usage would cause participants to perform in a biased manner, therefore falsely detecting more voices in bursts of noise. In Experiment 1, when cued to generate AVI, highly hallucination-prone participants showed a lower response bias than when performing a standard signal detection task, being more willing to report the presence of a voice in the noise. Participants not prone to hallucinations performed no differently between the two conditions. In Experiment 2, participants were not specifically instructed to use AVI, but retrospectively reported how often they engaged in AVI during the task. Highly hallucination-prone participants who retrospectively reported using imagery showed a lower response bias than did participants with lower proneness who also reported using AVI. Results are discussed in relation to prominent inner speech models of hallucinations.

From adversity to psychosis: pathways and mechanisms from specific adversities to specific symptoms

PURPOSE

Although there is considerable evidence that adversities in childhood such as social deprivation, sexual abuse, separation from parents, neglect and exposure to deviant parental communication are associated with psychosis in later life, most studies have considered broad diagnoses as outcomes. In this review we consider evidence for pathways between specific types of adversity and specific symptoms of psychosis.

METHODS

We present theoretical arguments for expecting some degree of specificity (although by no means perfect specificity) between different kinds of adversity and different symptoms of psychosis. We review studies that have investigated social-environmental risk factors for thought disorder, auditory-verbal hallucinations and paranoid delusions, and consider how these risk factors may impact on specific psychological and biological mechanisms.

RESULTS

Communication deviance in parents has been implicated in the development of thought disorder in offspring, childhood sexual abuse has been particularly implicated in auditory-verbal hallucinations, and attachment-disrupting events (e.g. neglect, being brought up in an institution) may have particular potency for the development of paranoid symptoms. Current research on psychological mechanisms underlying these symptoms suggests a number of symptom-specific mechanisms that may explain these associations.

CONCLUSIONS

Few studies have considered symptoms, underlying mechanisms and different kinds of adversity at the same time. Future research along these lines will have the potential to elucidate the mechanisms that lead to severe mental illness, and may have considerable clinical implications.

Externalizing biases and hallucinations in source-monitoring, self-monitoring and signal detection studies: a meta-analytic review

BACKGROUND

Cognitive models have postulated that auditory hallucinations arise from the misattribution of internally generated cognitive events to external sources. Several experimental paradigms have been developed to assess this externalizing bias in clinical and non-clinical hallucination-prone samples, including source-monitoring, verbal self-monitoring and auditory signal detection tasks. This meta-analysis aims to synthesize the wealth of empirical findings from these experimental studies.

METHOD

A database search was carried out for reports between January 1985 and March 2012. Additional studies were retrieved by contacting authors and screening references of eligible reports. Studies were considered eligible if they compared either (i) hallucinating and non-hallucinating patients with comparable diagnoses, or (ii) non-clinical hallucination-prone and non-prone participants using source-monitoring, verbal self-monitoring or signal detection tasks, or used correlational analyses to estimate comparable effects.

RESULTS

The analysis included 15 clinical (240 hallucinating patients and 249 non-hallucinating patients) and nine non-clinical studies (171 hallucination-prone and 177 non-prone participants; 57 participants in a correlation study). Moderate-to-large summary effects were observed in both the clinical and analogue samples. Robust and significant effects were observed in source-monitoring and signal detection studies, but not in self-monitoring studies, possibly due to the small numbers of eligible studies in this subgroup. The use of emotionally valenced stimuli led to effects of similar magnitude to the use of neutral stimuli.

CONCLUSIONS

The findings suggest that externalizing biases are important cognitive underpinnings of hallucinatory experiences. Clinical interventions targeting these biases should be explored as possible treatments for clients with distressing voices.

Testing a model of the relationship between childhood sexual abuse and psychosis in a first-episode psychosis group: the role of hallucinations and delusions, posttraumatic intrusions, and selective attention

Several theories suggest that posttraumatic intrusive symptoms are central to the relationship between childhood trauma (CT) and hallucinations and delusions in psychosis. Biased selective attention has been implicated as a cognitive process underlying posttraumatic intrusions. The current study sought to test theories of the relationship between childhood sexual abuse (CSA), hallucinations and delusions, posttraumatic intrusions, and selective attention in first-episode psychosis (FEP). Twenty-eight people with FEP and 21 nonclinical controls were assessed for CT and psychotic and posttraumatic stress symptoms and completed an emotional Stroop test using CSA-related and other words. Those with FEP and CSA had more severe hallucinations and delusions than those with FEP and without CSA. They also reported posttraumatic intrusions at clinical levels and showed selective attention to CSA-related words. The results are consistent with the posttraumatic intrusions account of hallucinations and delusions in those with CSA and psychosis.

A comprehensive review of auditory verbal hallucinations: lifetime prevalence, correlates and mechanisms in healthy and clinical individuals

Over the years, the prevalence of auditory verbal hallucinations (AVHs) have been documented across the lifespan in varied contexts, and with a range of potential long-term outcomes. Initially the emphasis focused on whether AVHs conferred risk for psychosis. However, recent research has identified significant differences in the presentation and outcomes of AVH in patients compared to those in non-clinical populations. For this reason, it has been suggested that auditory hallucinations are an entity by themselves and not necessarily indicative of transition along the psychosis continuum. This review will examine the presentation of auditory hallucinations across the life span, as well as in various clinical groups. The stages described include childhood, adolescence, adult non-clinical populations, hypnagogic/hypnopompic experiences, high schizotypal traits, schizophrenia, substance induced AVH, AVH in epilepsy, and AVH in the elderly. In children, need for care depends upon whether the child associates the voice with negative beliefs, appraisals and other symptoms of psychosis. This theme appears to carry right through to healthy voice hearers in adulthood, in which a negative impact of the voice usually only exists if the individual has negative experiences as a result of their voice(s). This includes features of the voices such as the negative content, frequency, and emotional valence as well as anxiety and depression, independently or caused by voices presence. It seems possible that the mechanisms which maintain AVH in non-clinical populations are different from those which are behind AVH presentations in psychotic illness. For example, the existence of maladaptive coping strategies in patient populations is one significant difference between clinical and non-clinical groups which is associated with a need for care. Whether or not these mechanisms start out the same and have differential trajectories is not yet evidenced. Future research needs to focus on the comparison of underlying factors and mechanisms that lead to the onset of AVH in both patient and non-clinical populations.

Memory binding in clinical and non-clinical psychotic experiences: how does the continuum model fare?

INTRODUCTION

Both clinical and non-clinical auditory hallucinations (AH) have been associated with source memory deficits, supporting a continuum of underlying cognitive mechanisms, though few studies have employed the same task in patient and nonpatient samples. Recent commentators have called for more debate on the continuum model of psychosis. Consequently, the current study investigated the continuity model of AH with reference to memory binding.

METHODS

We used an identical voice and word recognition memory task to assess binding in two separate studies of: (1) healthy hallucination-prone individuals and controls (30 high and 30 low scorers on the Launay-Slade Hallucination Scale-Revised) and (2) schizophrenia patient samples (32 with AH, 32 without AH) and 32 healthy controls.

RESULTS

There was no evidence of impaired binding in high hallucination-prone, compared to low hallucination-prone individuals. In contrast, individuals with schizophrenia (both with and without AH) had difficulties binding (remembering "who said what"), alongside difficulties remembering individual words and voices. Binding ability and memory for voices were also negatively linked to the loudness of hallucinated voices reported by patients with AH.

CONCLUSIONS

These findings suggest that different mechanisms may exist in clinical and non-clinical hallucinators, adding to the growing debate on the continuum model of psychotic symptoms.

Childhood trauma increases the risk of post-traumatic stress disorder in response to first-episode psychosis

OBJECTIVE

To investigate the relationship between childhood trauma, post-traumatic stress symptoms due to the experience of childhood trauma, and post-traumatic stress symptoms due to the experience of psychosis.

METHOD

The current study assessed childhood trauma and post-traumatic stress disorder (PTSD) symptoms as a result of both childhood trauma and psychosis using the Impact of Events Scale - Revised, in a group of 36 people with first-episode psychosis.

RESULTS

Reported rates of clinical level post-psychotic PTSD symptoms, childhood trauma and childhood trauma-related clinical level PTSD symptoms were 47% (95% CI 31-64%), 64% (95% CI 48-80%) and 39% (95% CI 23-55%), respectively. Reporting childhood trauma increased the risk of developing post-psychosis PTSD 27-fold (95% CI 2.96-253.80, p = 0.01). Having childhood trauma-related PTSD increased the risk of developing post-psychosis PTSD 20-fold (95% CI 3.38-123.25, p = 0.01). These risks were not explained by illness factors such as duration of untreated psychosis, age of onset or severity of psychotic symptoms. Those without post-psychotic PTSD symptoms at clinical levels were unlikely to report childhood trauma (6%; 95% CI 3-8%).

CONCLUSIONS

These results suggest the cognitive, social and biological consequences of childhood trauma can prevent effective recovery from the trauma of acute first-episode psychosis resulting in post-psychotic PTSD. Treatment strategies for post-psychotic PTSD must address childhood trauma and related PTSD.