Łukasz Gawęda

Impaired discrimination between imagined and performed actions in schizophrenia

The main aim of the present study was to investigate whether a specific type of source monitoring, namely self-monitoring for actions (differentiation between imagined and performed actions), is disrupted in schizophrenia. Persons diagnosed with schizophrenia (n=32) and healthy participants (n=32) were assessed with an action memory task. Simple actions were presented to the participants either verbally (short instructions) or nonverbally (icons). Some of the items required participants to physically perform the action whereas other actions had to be imagined. In the recognition phase of the study, participants were asked whether an action was previously displayed (verbally or nonverbally), whether it was a new action (not presented before), and if they had performed or imagined the action. In addition, participants were asked how confident they were in their decision. Participants in the group with schizophrenia significantly more often misattributed imagined actions as performed and vice versa and were more convinced about their wrong decision than participants in the control group. Patients revealed worse recognition for both verbal and nonverbal actions. In accordance with prior studies, we found that patients were less confident in their correct answers than healthy subjects. However, no enhanced confidence in incorrect answers was found. There was no observed significant relationship between source misattributions and the severity of psychopathological symptoms. Our findings suggest tentatively general source monitoring deficits in schizophrenia.

Impaired action self-monitoring in schizophrenia patients with auditory hallucinations

BACKGROUND It has been suggested that the process of discriminating between inner and outer experiences underlies auditory hallucinations (AHs). The aim of the present study was to investigate whether discrimination between imagined and performed action (i.e., action self monitoring) differed between schizophrenia patients with auditory hallucinations (AHs) and those without. METHOD Twenty-eight schizophrenia patients with AHs, twenty-six patients without AHs, and thirty-four healthy subjects were assessed with an action memory task. Simple actions were presented to the participant verbally (text) or non-verbally (icons). Some actions were physically performed and others were imagined. Following the learning phase, participants were presented with each action as well as new ones, were asked whether the action was presented verbally or non-verbally (actions presentation type discrimination), and whether the action was performed or imagined (self-monitoring). A confidence score related to self-monitoring responses was also obtained. RESULTS Patients with AHs more often remembered imagined actions as performed than patients without AHs and healthy controls. Schizophrenia patients made significantly more incorrect responses in action presentation type discrimination than healthy controls. Self-monitoring errors were followed by high confidence ratings in the schizophrenia group. No differences between patients with and without AH in old/new recognition emerged. CONCLUSIONS Our study suggests that action self-monitoring deficits but not impairments in discriminating presentation type are related to AHs. In the schizophrenia group, action-self monitoring errors were associated with overconfidence.

Cognitive biases mediate the relationship between temperament and character and psychotic-like experiences in healthy adults.

Psychotic-like experiences (PLEs) are frequently reported in the general population. Healthy individuals reporting PLEs have a similar personality profile to people with psychosis; however, the mechanisms by which personality influences PLEs are unclear. This study tests the hypothesis that cognitive biases mediate the relationship between two dimensions of personality (i.e. temperament and character) and positive and negative PLEs. Two hundred and ninety-six healthy participants were assessed using the Community Assessment of Psychic Experiences scale, the Temperament and Character Inventory and the Davos Scale for Cognitive Biases. We performed multiple stepwise regression analysis and mediation analysis according to Baron and Kenny׳s method. Harm-avoidance and self-directedness personality dimensions significantly predicted PLEs frequency. High self-transcendence and lower cooperativeness predicted positive PLEs. Cognitive biases were significant mediators in relationships between temperament, character and both positive and negative PLEs. In particular, attention to threat and external attribution biases fully mediate the relationship between cooperativeness and positive PLEs. Other cognitive biases partially mediate the relationships between self-transcendence and positive PLEs and self-directedness, harm-avoidance and negative PLEs. Our study tentatively suggests that personality may influence PLEs via the cognitive bias pathway.

A relationship between hallucination proneness and character and temperament: A mediating role of meta-cognitive beliefs in a non-clinical sample

We investigated a mediating role of meta-cognitions in the relationship between Cloningers temperament and character dimensions and hallucination proneness among healthy subjects (n=135). Two character dimensions-self-directedness and self-transcendence-were related to hallucination proneness. Negative beliefs about uncontrollability of thoughts partially mediated the relationship between these two character dimensions and hallucination proneness.

Interactions between variation in candidate genes and environmental factors in the etiology of schizophrenia and bipolar disorder : a systematic review

Schizophrenia and bipolar disorder (BD) are complex and multidimensional disorders with high heritability rates. The contribution of genetic factors to the etiology of these disorders is increasingly being recognized as the action of multiple risk variants with small effect sizes, which might explain only a minor part of susceptibility. On the other site, numerous environmental factors have been found to play an important role in their causality. Therefore, in recent years, several studies focused on gene × environment interactions that are believed to bridge the gap between genetic underpinnings and environmental insults. In this article, we performed a systematic review of studies investigating gene × environment interactions in BD and schizophrenia spectrum phenotypes. In the majority of studies from this field, interacting effects of variation in genes encoding catechol-O-methyltransferase (COMT), brain-derived neurotrophic factor (BDNF), and FK506-binding protein 5 (FKBP5) have been explored. Almost consistently, these studies revealed that polymorphisms in COMT, BDNF, and FKBP5 genes might interact with early life stress and cannabis abuse or dependence, influencing various outcomes of schizophrenia spectrum disorders and BD. Other interactions still require further replication in larger clinical and non-clinical samples. In addition, future studies should address the direction of causality and potential mechanisms of the relationship between gene × environment interactions and various categories of outcomes in schizophrenia and BD.

The role of self-disturbances and cognitive biases in the relationship between traumatic life events and psychosis proneness in a non-clinical sample

BACKGROUND Traumatic life events have been established as an environmental risk factor for psychosis. However, the exact mechanisms by which traumatic life events increase risk for psychosis are unknown. In the present study we tested an integrative model of traumatic life events being related to psychosis proneness via self-disturbances and cognitive biases. METHODS The sample consisted of 653 healthy people. Traumatic life events, self-disturbances, cognitive biases and psychosis proneness were assessed with self-report questionnaires. The direct and an indirect model of the relationship between traumatic life events and psychosis proneness were compared using path analyses with structural equation modelling in a cross-sectional study. RESULTS There was a significant direct effect of traumatic life events on psychosis proneness. However, path analysis suggested better fit of the indirect model including paths from trauma to psychosis proneness via cognitive biases and self-disturbances. There were significant paths from traumatic life events to cognitive biases and self-disorders. Self-disorders significantly predicted cognitive biases. Finally, cognitive biases and self-disorders significantly predicted psychosis proneness. Exclusion of any paths, apart from direct path in the model, significantly reduced model fitness. DISCUSSION The results revealed that a direct relationship between trauma and psychosis proneness became insignificant when taking into account the influence of self-disorders and cognitive biases. This suggests that the interactions between disrupted self-experience, impaired information processing and traumatic life events are of importance in psychosis proneness. This model should be further tested in a longitudinal study on a clinical sample.

Meta-cognitive beliefs as a mediator for the relationship between Cloninger’s temperament and character dimensions and depressive and anxiety symptoms among healthy subjects

BACKGROUND Previous studies suggest that temperament and character may impact depression and anxiety through dysfunctional cognition. This study targets the mediating role of meta-cognitive beliefs in the relationship between Cloningers temperament and character dimensions and symptoms of depression and anxiety. METHOD One hundred and sixty-one healthy subjects filled out Cloningers Temperament Character Inventory (TCI), a Metacognitions Questionnaire (MCQ), the Beck Depression Inventory (BDI) and the State and Trait Anxiety Inventory (STAI). Correlation and mediation analyses according to Baron and Kennys method were performed. RESULTS Harm avoidance (HA) and self-directedness (SD) were related to depression and anxiety. HA was related to negative beliefs about uncontrollability of thoughts and to beliefs about cognitive confidence. SD was associated with the same types of meta-cognitive beliefs and with general negative beliefs. Cooperativeness (CO) was related to positive beliefs about worry, beliefs about cognitive confidence and to general negative beliefs. Self-transcendence (ST) was related to all types of meta-cognitive beliefs. Mediation analysis revealed that the relationship between HA and depression and anxiety is partially mediated by certain types of meta-cognitive beliefs. The same results were obtained for the relationship between SD and depression and anxiety. General negative beliefs fully mediated the relationship between CO and depression and the relationship between ST and anxiety. CONCLUSIONS Meta-cognitive beliefs mediate the relationship between temperament and character dimension and depressive and anxiety symptoms, thus providing further evidence for the meta-cognitive theory of emotional disorders as presented by Wells and Matthews (Behav Res Ther 1996;32:867-870).

A new paradigm to measure probabilistic reasoning and a possible answer to the question why psychosis-prone individuals jump to conclusions.

Jumping to conclusions (JTC) distinguishes patients with schizophrenia from both healthy and psychiatric controls. JTC is typically assessed using the beads task, which, however, faces a number of limitations as to its interpretability and reliability. The present study set out to validate a new paradigm to assess JTC: the box task. We adopted a psychometric psychosis proneness approach and divided a large population sample into participants who scored high versus low on a scale tapping psychosis-like experiences. Participants performed a variant of the original beads task along with a new JTC task, the box task, with or without time pressure. The box task requires participants to infer which of two ball colors will be more prevalent in a matrix of boxes. The box task and the beads task were significantly correlated at a medium effect size, thus demonstrating criterion validity for the box task. As hypothesized, participants who scored high on psychosis-like experiences showed particularly strong JTC and a decreased decision threshold relative to low scorers, especially in the box task version with time pressure; in contrast, group differences in the beads tasks only achieved trend-wise significance. Mediation analyses showed that fewer draws to decisions were predicted by either a lower decision threshold or by higher initial probability estimates for the dominant item. The study establishes the criterion and construct validity of a new JTC task. Its advantages over the traditional beads task are better comprehensibility and usability; multiple parallel versions can be created thus raising reliability.

The role of unhelpful metacognitive beliefs in psychosis: Relationships with positive symptoms and negative affect

The Self-Regulatory Executive Function (s-REF) model assumes that a common set of unhelpful metacognitive beliefs have a central role in predisposition to psychological disorder and the maintenance of symptoms and distress. This research aims to test whether the five unhelpful metacognitive beliefs implicated in the model are associated with positive symptoms of psychosis and whether they are a better predictor of negative affect than topological characteristics of positive symptoms. A sample of people with psychosis completed a semi-structured interview about psychotic symptoms and self-report measures of metacognitive beliefs (MCQ-30), anxiety and depression. Hierarchical multiple regression analyses suggested that unhelpful metacognitive beliefs predict negative affect in people with psychosis over and above symptom frequency and other topological characteristics of symptoms captured by the Psychotic Symptoms Rating Scale (PSYRATS). The findings support the application of the metacognitive model to emotional distress in people with psychosis.

Self-disturbances, cognitive biases and insecure attachment as mechanisms of the relationship between traumatic life events and psychotic-like experiences in non-clinical adults - A path analysis

Although traumatic life events have been linked to psychotic-like experiences, the mechanisms of the relationship remain unclear. We investigated whether insecure (anxious and avoidant) attachment styles, cognitive biases and self-disturbances serve as significant mediators in the relationship between traumatic life events and psychotic-like experiences in non-clinical sample. Six-hundred and ninety healthy participants (522 females) who have not ever been diagnosed with psychiatric disorders took part in the study. Participants completed self-report scales that measure traumatic life events, psychotic-like experiences, cognitive biases, attachment styles and self-disturbances. Our model was tested with path analysis. Our integrated model fit to the data with excellent goodness-of-fit indices. The direct effect was significantly reduced after the mediators were included. Significant pathways from traumatic life events to psychotic-like experiences were found through self-disturbances and cognitive biases. Traumatic life events were associated with anxious attachment through cognitive biases. Self-disturbances, cognitive biases and anxious attachment had a direct effect on psychotic-like experiences. The results of our study tentatively suggest that traumatic life events are related with psychotic-like experiences through cognitive biases and self-disturbances. Further studies in clinical samples are required to verify our model.