Distinguishing schizophrenia spectrum from non-spectrum disorders among young patients with first episode psychosis and at high clinical risk: The role of basic self-disturbance and neurocognition

Abnormal Oculomotor Corollary Discharge Signaling as a Trans-diagnostic Mechanism of Psychosis

BACKGROUND AND HYPOTHESIS

Corollary discharge (CD) signals are "copies" of motor signals sent to sensory areas to predict the corresponding input. They are a posited mechanism enabling one to distinguish actions generated by oneself vs external forces. Consequently, altered CD is a hypothesized mechanism for agency disturbances in psychosis. Previous studies have shown a decreased influence of CD signals on visual perception in individuals with schizophrenia-particularly in those with more severe positive symptoms. We therefore hypothesized that altered CD may be a trans-diagnostic mechanism of psychosis.

STUDY DESIGN

We examined oculomotor CD (using the blanking task) in 49 participants with schizophrenia or schizoaffective disorder (SZ), 36 bipolar participants with psychosis (BPP), and 40 healthy controls (HC). Participants made a saccade to a visual target. Upon saccade initiation, the target disappeared and reappeared at a horizontally displaced position. Participants indicated the direction of displacement. With intact CD, participants can make accurate perceptual judgements. Otherwise, participants may use saccade landing site as a proxy of pre-saccadic target to inform perception. Thus, multi-level modeling was used to examine the influence of target displacement and saccade landing site on displacement judgements.

STUDY RESULTS

SZ and BPP were equally less sensitive to target displacement than HC. Moreover, regardless of diagnosis, SZ and BPP with more severe positive symptoms were more likely to rely on saccade landing site.

CONCLUSIONS

These results suggest that altered CD may be a trans-diagnostic mechanism of psychosis.

Remember walking in their shoes? The relation of self-referential source memory and emotion recognition

Deficits in the ability to read the emotions of others have been demonstrated in mental disorders, such as dissociation and schizophrenia, which involve a distorted sense of self. This study examined whether weakened self-referential source memory, being unable to remember whether a piece of information has been processed with reference to oneself, is linked to ineffective emotion recognition. In two samples from a college and community, we quantified the participants' ability to remember the self-generated versus non-self-generated origins of sentences they had previously read or partially generated. We also measured their ability to read others' emotions accurately when viewing photos of people in affect-charged situations. Multinomial processing tree modelling was applied to obtain a measure of self-referential source memory that was not biased by non-mnemonic factors. Our first experiment with college participants revealed a positive correlation between correctly remembering the origins of sentences and accurately recognising the emotions of others. This correlation was successfully replicated in the second experiment with community participants. The current study offers evidence of a link between self-referential source memory and emotion recognition.

I don't understand how I feel: mediating role of impaired self-mentalizing in the relationship between childhood adversity and psychosis spectrum experiences

Introduction

Childhood adversity is associated with the severity of multiple dimensions of psychosis, but the mechanisms underpinning the close link between the two constructs is unclear. Mentalization may underlie this relationship, as impaired mentalizing is found in various stages of the psychosis continuum. Nonetheless, the differential roles of self- and other-mentalizing in psychosis are not well understood.

Methods

Parallel multiple mediation was conducted for the relationship between a diverse range of childhood adversity types, including intentional and nonintentional harm, and schizotypy (positive, negative, disorganized), psychotic-like experiences (PLE) and paranoia via self-mentalizing (attention to emotions and emotional clarity) and other-mentalizing in n = 1,156 nonclinically ascertained young adults.

Results

Significant parallel multiple mediation models were found for all psychotic outcomes except negative schizotypy. The associations between intentionally harmful childhood adversity and psychotic outcomes were significantly mediated by increased attention to emotions for most models and decreased emotional clarity for some models. No significant mediation was found for parental loss. Paternal abuse was only mediated by attention to emotions whereas the effects of maternal abuse were mediated by attention to emotions and emotional clarity. Other-mentalizing only showed mediating effects on one of thirty models tested.

Conclusion

Results highlight the mediating role of impaired self-mentalizing in the association between childhood adversity and psychosis. This is consistent with disturbances of self-concept and self-boundary characterizing, in particular, the positive dimension of psychosis. Maternal versus paternal figures may contribute differentially to the development of mentalizing. These results could inform future preventative interventions, focusing on the development and maintenance of self-mentalizing.

Association between the rs6313 polymorphism in the 5-HTR2A gene and the efficacy of antipsychotic drugs

BACKGROUND

Prescribing the optimal antipsychotic treatment to schizophrenia is very important as it is well established that patients have different sensitivity to the available antipsychotic drugs. The genotype of the HTR2A T102C (rs6313) polymorphism has been suggested to affect the efficacy of antipsychotic drugs, but the results of different studies have been inconsistent METHODS: In this study, a meta-analysis was used to ascertain the association between allele and genotype polymorphism of rs6313 and the efficacy of antipsychotic drugs. Related studies publicated from January 1995 to December 2021 were retrieved from PubMed, Embase, ScienceDirect, and Web of Science databases. The correlations between allele and genotype polymorphism of rs6313 and the responder rate and scale score reduction rate of antipsychotics were analyzed. In addition, subgroup analyses were performed on time, drug, and ethnicity.

RESULTS

A total of 18 studies were included. The meta-analysis showed that allele and genotype polymorphisms at the rs6313 locus overall were not associated with antipsychotic drug responder rate or scale score reduction rate. Ethnicity subgroup analysis showed that antipsychotic drugs were more effective in patients with allele T in the Caucasian population. Indian patients with the TT genotype had the lowest scale score reduction rate and poor drug treatment effect. East Asian patients with the TC genotype had better treatment effect, whereas in patients with the CC genotype, the treatment was less effective. Drug subgroup analysis showed that patients with the TC genotype treated with clozapine had the highest responder rate and score reduction rate.

CONCLUSIONS

The association between rs6313 polymorphism and the efficacy of antipsychotic drugs is mainly influenced by drug and ethnicity. Caucasian patients with the T allele respond better to drug therapy, and Asian patients with TC genotype. The TC genotype was also a good predictor of the efficacy of clozapine treatment.

Prevalence and assessment of self-disorders in the schizophrenia spectrum: a systematic review and meta-analysis

Self-disorders have been proposed as the "clinical core" of the schizophrenia spectrum. This has been explored in recent studies using self-disorder assessment tools. However, there are few systematic discussions of their quality and utility. Therefore, a literature search was performed on Medline, Embase, PsychINFO, PubMed and the Web of Science. Studies using these assessment tools to explore self-disorders within schizophrenia spectrum disorders (SSDs) were included. A meta-analysis was performed on the outcomes of total self-disorder score and odds ratios of self-disorders, using Comprehensive Meta-Analysis software. Weighted pooled effect sizes in Hedge's g were calculated using a random-effects model. 15 studies were included, giving a sample of 810 participants on the schizophrenia spectrum. Self-disorders showed a greater aggregation within schizophrenia spectrum groups compared to non-schizophrenia spectrum groups, as measured with the Bonn Scale for the Assessment of Basic Symptoms (Hedge's g = 0.774, p < 0.01) and Examination of Anomalous Self-Experiences (Hedge's g = 1.604, p < 0.01). Also, self-disorders had a greater likelihood of occurring within SSDs (odds ratio = 5.435, p < 0.01). These findings help to validate self-disorders as a core clinical feature of the broad schizophrenia spectrum.

Integrating trauma, self-disturbances, cognitive biases, and personality into a model for the risk of psychosis: a longitudinal study in a non-clinical sample

The hypothesis of the psychosis continuum enables to study the mechanisms of psychosis risk not only in clinical samples but in non-clinical as well. The aim of this longitudinal study was to investigate self-disturbances (SD), a risk factor that has attracted substantial interest over the last two decades, in combination with trauma, cognitive biases and personality, and to test whether SD are associated with subclinical positive symptoms (PS) over a 12-month follow-up period. Our study was conducted in a non-clinical sample of 139 Polish young adults (81 females, age M = 25.32, SD = 4.51) who were selected for frequent experience of subclinical PS. Participants completed self-report questionnaires for the evaluation of SD (IPASE), trauma (CECA.Q), cognitive biases (DACOBS) and personality (TCI), and were interviewed for subclinical PS (CAARMS). SD and subclinical PS were re-assessed 12 months after baseline measurement. The hypothesized model for psychosis risk was tested using path analysis. The change in SD and subclinical PS over the 12-month period was investigated with non-parametric equivalent of dependent sample t-tests. The models with self-transcendence (ST) and harm avoidance (HA) as personality variables were found to be well-fitted and explained 34% of the variance in subclinical PS at follow-up. Moreover, we found a significant reduction of SD and subclinical PS after 12 months. Our study suggests that combining trauma, cognitive biases, SD and personality traits such as ST and HA into one model can enhance our understanding of appearance as well as maintenance of subclinical PS.

Exploring multimodal hallucinations and disturbances in the basic and bodily self: A cross-sectional study in a non-clinical sample

The bodily self is key to emotional embodiment, which is important for social functioning and emotion regulation. There is a paucity of research systematically assessing how basic and bodily self-disturbances relate to multimodal hallucinations. This study hypothesised that participants with greater hallucination-proneness would report greater degrees of basic and bodily self-disturbance and would demonstrate more ambiguous and less discrete mapping of emotional embodiment. Stage one screened non-clinical participants' degree of hallucination-proneness. Stage two participants completed seven further questionnaires. Hierarchical linear regression modelled the influence of hallucination-proneness and covariates on measures of basic and bodily self-disturbance and sensed presence. Stage two participants also completed a computerised body mapping task (EmBODY) which assessed emotional embodiment. Topographical maps were generated to compare patterns of embodiment between high and low hallucination-proneness groups. 55 respondents participated in stage two, with 18 participants from the high or low hallucination-proneness groups completing EmBODY. In the hierarchical regression analyses, the addition of a measure of hallucination proneness in the final step only increased predictive power where the dependent variable assessed sensed presence (p = 0.035 and p = 0.009, respectively). The EmBODY data revealed that participants with low hallucination-proneness consistently reported more bodily activation across 14 emotional states, whereas the high hallucination-proneness group reported more deactivation. In conclusion, hallucination-proneness was most strongly associated with sensed presence experiences. Patterns of embodiment appeared similar between the two groups, despite consistent differences in activation and deactivation. These findings are exploratory and need to be confirmed in a larger sample.

Self-disorders and psychopathology: a systematic review

In foundational texts on schizophrenia, the mental disorder was constitutively linked to a specific disintegration of subjectivity (often termed a self-disorder). Apart from Scharfetter's work on ego-pathology, research on self-disorders generally faded into oblivion, and self-disorders were only rediscovered as notable psychopathological features of the schizophrenia spectrum nearly two decades ago. Subsequently, the Examination of Anomalous Self-Experience (EASE) scale was constructed to allow systematic assessment of non-psychotic self-disorders. This Review is the first systematic review of empirical studies on self-disorders based on the EASE or other related scales. The results consistently show that self-disorders hyper-aggregate in schizophrenia spectrum disorders but not in other mental disorders; that self-disorders are found in individuals at a clinical risk of developing psychosis; that self-disorders show a high degree of temporal stability; that self-disorders predict the later development of schizophrenia spectrum disorders; and that self-disorders correlate with the canonical dimensions of the psychopathology of schizophrenia, impaired social functioning, and suicidality. Issues with the methods of the reviewed literature are critically discussed and the role of self-disorders in clinical psychiatry and future research is outlined.

Neural Correlates of Aberrant Salience and Source Monitoring in Schizophrenia and At-Risk Mental States-A Systematic Review of fMRI Studies

Cognitive biases are an important factor contributing to the development and symptom severity of psychosis. Despite the fact that various cognitive biases are contributing to psychosis, they are rarely investigated together. In the current systematic review, we aimed at investigating specific and shared functional neural correlates of two important cognitive biases: aberrant salience and source monitoring. We conducted a systematic search of fMRI studies of said cognitive biases. Eight studies on aberrant salience and eleven studies on source monitoring were included in the review. We critically discussed behavioural and neuroimaging findings concerning cognitive biases. Various brain regions are associated with aberrant salience and source monitoring in individuals with schizophrenia and the risk of psychosis. The ventral striatum and insula contribute to aberrant salience. The medial prefrontal cortex, superior and middle temporal gyrus contribute to source monitoring. The anterior cingulate cortex and hippocampus contribute to both cognitive biases, constituting a neural overlap. Our review indicates that aberrant salience and source monitoring may share neural mechanisms, suggesting their joint role in producing disrupted external attributions of perceptual and cognitive experiences, thus elucidating their role in positive symptoms of psychosis. Account bridging mechanisms of these two biases is discussed. Further studies are warranted.