Emmanuelle Peters

Need for Closure and jumping-to-conclusions in delusion-prone individuals

Members of the general population were screened for delusion-proneness using the Peters et al. Delusions Inventory (PDI). Two groups were formed from the participants who scored in the upper and lower quartiles of the PDI and compared on a probability judgment task and on the Need for Closure scale (NFC). The study investigated whether the “jump-to-conclusions” (JTC) reasoning bias, characteristic of deluded participants, could be found in delusion-prone individuals. NFC was investigated as a motivational factor that may correlate with this reasoning bias. Evidence for the existence of the data-gathering, but not the probability judgment, part of the JTC reasoning bias was found in the delusion-prone individuals. This group also scored significantly higher on the NFC scale. As the data-gathering reasoning bias was found in delusion-prone individuals this suggests that it may be involved in the formation, rather than merely the maintenance, of delusional beliefs.

A quantitative genetic analysis of schizotypal personality traits

BACKGROUND Previous twin studies investigating the heritability of schizotypy have often had limited power and have failed to measure the disorganization/social anxiety component. METHOD Seven hundred and thirty-three female twin pairs, drawn from the Institute of Psychiatry Volunteer Twin Register, completed the Oxford-Liverpool Inventory of Feelings and Experiences and the Peters et al. Delusions Inventory. Structural equation modelling was carried out on scores for MZ and DZ twin pairs. RESULTS The best fitting models for all scales comprised additive genetic and unique environmental effects. Heritability was estimated at approximately 50% for most scales, although it was lower at 37% for the PDI scale. Multivariate structural equation model fitting revealed a best-fitting model in which additive genetic and unique environmental influences act through a single common pathway for Cognitive Disorganization, Unusual Experiences and the PDI, and through a separate common pathway for Cognitive Disorganization and Introvertive Anhedonia. CONCLUSIONS The various components of schizotypy are moderately heritable. Multivariate model fitting indicates that at least two latent factor structures are required to account for the covariation between the various components of schizotypy. The positive and negative components of schizotypy are relatively genetically independent, although each in turn may be related to Cognitive Disorganization.

Disease, deficit or denial? Models of poor insight in psychosis

Objective:  To examine the evidence for the three kinds of aetiological model that dominate the current literature on poor insight in psychosis: clinical models, the neuropsychological model, and the psychological denial model.

Auditory verbal hallucinations in persons with and without a need for care

Auditory verbal hallucinations (AVH) are complex experiences that occur in the context of various clinical disorders. AVH also occur in individuals from the general population who have no identifiable psychiatric or neurological diagnoses. This article reviews research on AVH in nonclinical individuals and provides a cross-disciplinary view of the clinical relevance of these experiences in defining the risk of mental illness and need for care. Prevalence rates of AVH vary according to measurement tool and indicate a continuum of experience in the general population. Cross-sectional comparisons of individuals with AVH with and without need for care reveal similarities in phenomenology and some underlying mechanisms but also highlight key differences in emotional valence of AVH, appraisals, and behavioral response. Longitudinal studies suggest that AVH are an antecedent of clinical disorders when combined with negative emotional states, specific cognitive difficulties and poor coping, plus family history of psychosis, and environmental exposures such as childhood adversity. However, their predictive value for specific psychiatric disorders is not entirely clear. The theoretical and clinical implications of the reviewed findings are discussed, together with directions for future research.

Insight, distress and coping styles in schizophrenia

Background The stigma and negative societal views attached to schizophrenia can make the diagnosis distressing. There is evidence that poor insight into symptoms of the disorder and need for treatment may reflect the use of denial as a coping style. However, the relationships between insight and other coping styles have seldom been investigated. Method We examined the associations between insight, distress and a number of coping styles in 65 outpatients with schizophrenia (final n = 57) in a cross-sectional study. Results We found that (i) awareness of symptoms and problems correlated with greater distress, (ii) ‘preference for positive reinterpretation and growth’ coping style correlated with lower distress and with lower symptom awareness (re-labelling), (iii) ‘preference for mental disengagement’ coping style correlated with greater distress and lower awareness of problems, and (iv) ‘social support-seeking’ coping style correlated with greater awareness of illness, but not distress. No relationship occurred between the use of ‘denial’ as a coping style and insight or distress. Conclusions Our findings demonstrate that awareness of illness and related problems is associated with greater distress in schizophrenia. However, this investigation has not supported a simple psychological denial explanation for this relationship, as complex relationships emerged between different dimensions of insight and coping styles. The negative association between ‘positive reinterpretation and growth’ and distress suggests that adopting this style may lead to re-labelling symptoms in a less distressing way. Avoidant and isolating styles of coping both appear unhelpful. Psychological interventions should aim to promote more active coping such as discussing a mental health problem with others.

Dorsolateral prefrontal cortex activity predicts responsiveness to cognitive-behavioral therapy in schizophrenia.

Background Given the variable response to cognitive–behavioral therapy (CBT) when added to antipsychotic medication in psychosis and the evidence for a role of pretherapy level of frontal lobe–based cognitive function in responsiveness to CBT in other disorders, this study examined whether pretherapy brain activity associated with working memory neural network predicts clinical responsiveness to CBT in schizophrenia. Methods Fifty-two outpatients stable on medication with at least one distressing symptom of schizophrenia and willing to receive CBT in addition to their usual treatment and 20 healthy participants underwent functional magnetic resonance imaging during a parametric n-back task. Subsequently, 26 patients received CBT for psychosis (CBT+treatment-as-usual [TAU], 19 completers) for 6–8 months, and 26 continued with TAU alone (17 completers). Symptoms in both patient groups were assessed (blindly) at entry and follow-up. Results The CBT+TAU and TAU-alone groups did not differ clinically or in performance at baseline. The CBT+TAU group showed significant improvement in relation to the TAU-alone group, which showed no change, at follow-up. Stronger dorsolateral prefrontal cortex (DLPFC) activity (within the normal range) and DLPFC–cerebellum connectivity during the highest memory load condition (2-back > 0-back) were associated with post-CBT clinical improvement. Conclusions DLPFC activity and its connectivity with the cerebellum predict responsiveness to CBT for psychosis in schizophrenia. These effects may be mediated by PFC–cerebellum contributions to executive processing.

Neurological basis of poor insight in psychosis: A voxel-based MRI study

Background As a reflection of poor insight, people with schizophrenia often disagree with carers and clinicians about whether (a) their experiences are abnormal, (b) they are mentally ill, and (c) they need treatment. Methods This study used voxel-based morphometry to identify the associations between total and regional grey matter volumes and self-reported and observer-rated insight in 52 patients with schizophrenia or schizoaffective disorder. Thirty healthy participants were also studied. Results There were positive associations in patients between (i) the ability to recognise experiences as abnormal and the total and right superior temporal gyrus grey matter volumes, (ii), awareness of problems (‘something wrong’) and the left precuneus grey matter volume and (iii) awareness of symptoms and attributing them to illness and grey matter volumes in the left superior–middle temporal gyrus and the right inferior temporal and lateral parietal gyri. The ‘recognition of the need for medication’ dimension did not correlate with total or any regional grey matter volumes. Relative to controls, patients had less total and regional grey matter volumes in the thalamus and middle occipital and superior temporal gyri. Conclusions Lower grey matter volumes in the temporal and parietal regions that have been implicated in self-monitoring, working memory and access to internal mental states are associated with poor insight on certain dimensions in psychosis.

The incidence of schizotypy among cannabis and alcohol users

Schizotypy research has revealed associations between positive schizotypal symptomatology and substance use but has not related substance use to important schizotypal traits such as anhedonia. Users and nonusers of cannabis and alcohol completed the Oxford-Liverpool Inventory of Feelings and Experiences, the Peters Delusion Inventory, and the Hospital Anxiety and Depression Scale. Cannabis users scored significantly higher on Unusual Experiences, a scale measuring positive schizotypal symptomatology. Both cannabis and alcohol usage were associated with significantly lower scores on Introvertive Anhedonia, which represents negative symptomatology. Delusional ideation and delusional conviction were significantly higher in cannabis users, but for delusional conviction this was only true for users who also drank alcohol. Neither anxiety or depression scores were higher in cannabis users, but delusional ideation correlated with both anxiety and depression, thus providing mixed support for the idea of the “happy schizotype. ” Overall, these results suggest that cannabis and alcohol usage is related to different dimensions of psychosis-proneness that broadly parallel the relationship between substance use and positive and negative schizophrenic symptoms, thus supporting the continuity view of psychosis and the multidimensionality of psychosis-proneness.

Psychotic-Like Experiences, Appraisals, and Trauma

This study examined some of the predictions made by cognitive models of psychosis, specifically the potential contribution of appraisals and trauma to the development of “need for care.” Two groups reporting psychotic-like experiences with and without a “need for care” were compared on types of experiences, appraisals of these experiences, distress, and trauma. Both groups reported similar overall levels of psychotic-like experiences, but were characterized by distinct types of experiences. The clinical group was more distressed, endorsed more externalizing and personalizing appraisals, and fewer psychological/normalizing apraisals of their experiences than the nonclinical group. Both groups showed high rates of trauma, and interpersonal trauma was associated with more personalizing and fewer psychological/normalizing appraisals. These results suggest that “need for care” is characterized by distress and personalizing appraisals, but not by a higher incidence of trauma. The role of interpersonal trauma, specifically, may be to predispose to a “paranoid” world view.

Psychological Therapies for Auditory Hallucinations (Voices): Current Status and Key Directions for Future Research

This report from the International Consortium on Hallucinations Research considers the current status and future directions in research on psychological therapies targeting auditory hallucinations (hearing voices). Therapy approaches have evolved from behavioral and coping-focused interventions, through formulation-driven interventions using methods from cognitive therapy, to a number of contemporary developments. Recent developments include the application of acceptance- and mindfulness-based approaches, and consolidation of methods for working with connections between voices and views of self, others, relationships and personal history. In this article, we discuss the development of therapies for voices and review the empirical findings. This review shows that psychological therapies are broadly effective for people with positive symptoms, but that more research is required to understand the specific application of therapies to voices. Six key research directions are identified: (1) moving beyond the focus on overall efficacy to understand specific therapeutic processes targeting voices, (2) better targeting psychological processes associated with voices such as trauma, cognitive mechanisms, and personal recovery, (3) more focused measurement of the intended outcomes of therapy, (4) understanding individual differences among voice hearers, (5) extending beyond a focus on voices and schizophrenia into other populations and sensory modalities, and (6) shaping interventions for service implementation.