The nature of delusions remains unclear despite their interest to researchers and importance in psychopathology. Here we present a review of the contributions from various disciplines, principally ...cognitive neuroscience, towards a new understanding.
Narrative review of published research.
The main areas of activity revolve around reasoning biases, attributional and attentional biases, theory of mind, and the role of emotion, with each area beginning to be explored using functional neuroimaging techniques. Of heuristic interest are neurological models, which include confabulation and delusional misidentification and the one- versus two-stage (perceptual versus reasoning plus perceptual) accounts of the latter.
These different approaches are shown to each highlight mechanisms which are suggested to cause, contribute to, or modulate the genesis and form of delusions. Such contributions coupled with traditional phenomenological methods should provide the foundations for a cognitive neuropsychiatry of delusions.
Insight in psychosis and schizophrenia is considered a complex biopsychosocial phenomenon. Premorbid personality is regarded by some authors as part of the substrate to many psychiatric phenomena, ...but it is not clear if this applies to insight.
To examine longitudinal relationships between personality traits and insight dimensions in first-episode psychosis.
One hundred consecutive antipsychotic-naïve first-episode nonaffective psychotic patients admitted to hospital were included in the study. Eighty-one patients completed at 1 month a premorbid personality evaluation, plus baseline, and 6-month insight assessments. We used the Assessment and Documentation of Psychopathology inventory for assessing insight dimensions (not feeling ill, lack of insight, and refusal of treatment) and the Personality Assessment Schedule for ascertaining 5 dimensions of premorbid personality (schizoid, passive-dependent, anancastic, sociopathic, and schizotypy).
At baseline, personality dimensions did not show any association with insight dimensions, with the exception of schizotypy traits. At 6 months, schizoid and sociopathic personality showed a significant association with not feeling ill (r = .30, P ≤ .007; r = .27, P = .01) and lack of insight (r = .36, P = .001; r = .41, P < .001), respectively. When we calculated insight change, schizoid and sociopathic personality had moderate correlation with the lack of insight dimension (r = -.34, P = .002; r = .38, P < .001, respectively). After applying partial correlations for potential confounders and Bonferroni correction, the associations remained significant. Moreover, using a regression model, sociopathic and schizoid personality significantly predicted lack of insight at 6 months and change from baseline to the 6 months assessment.
Sociopathic and schizoid personality dimensions were not only significantly associated with lack of insight at 6 months but also predicted change on lack of insight over 6 months. Therefore, exploring premorbid personality traits at the beginning of a psychotic episode may be helpful in identifying patients at high risk for lack of insight during the initial course of the illness.
Delusions and hallucinations are classic positive symptoms of schizophrenia. A contemporary cognitive theory called the 'forward output model' suggests that the misattribution of self-generated ...actions may underlie some of these types of symptoms, such as delusions of control - the experience of self-generated action being controlled by an external agency. In order to examine the validity of this suggestion, we performed a longitudinal functional magnetic resonance imaging (fMRI) study examining neuronal activation associated with motor movement during acute psychosis.
We studied brain activation using fMRI during a motor task in 11 patients with schizophrenia and 9 healthy controls. The patient group was tested at two time points separated by 6-8 weeks.
At initial testing, the patient group had a mean Positive and Negative Syndrome Scale score of 56.3, and showed significantly increased activation within the left inferior parietal lobe (IPL) compared to controls. Patients reported significantly decreased positive symptoms at 6-8 week followup and IPL activation had returned to normal. Our results demonstrate that first-rank positive symptoms are associated with hyperactivation in the secondary somatosensory cortex (IPL).
These findings lend further credence to the theory that a dysfunction in the sensory feedback system located in the IPL, and which is thought to underlie our sense of agency, may contribute to the aetiology of delusions of control.
Abstract Lack of insight is a commonly observed problem in patients with psychosis and schizophrenia. Clinical insight in patients has been associated with low mood. Cognitive insight is a recently ...defined concept, relating to the ability to self-reflect and the degree to which patients are over-confident regarding their interpretations of illness-related experiences, and is related to clinical insight. We therefore sought to investigate whether there is a positive relationship between cognitive insight and mood. A literature search identified 17 relevant papers published between 2004 and 2014. Our analysis indicated that there was a small but significant positive correlation between the composite index (CI) of the Beck Cognitive Insight Scale (BCIS) and depression scores, but this was driven by a significant positive relationship between depression and the BCIS self-reflection (SR) sub-scale, where low mood was related to higher SR scores. There was no significant relationship between the self-certainty sub-scale and depression. Post-hoc analysis indicated that different depression scales did not significantly affect the relationship with SR. Our results support the idea that cognitive insight is significantly related to mood in schizophrenia, and the effect size is similar to that between clinical insight and mood. Potential applications of this knowledge into treatment and rehabilitation are discussed and a model of cognitive insight is proposed.
Background:
Theory of mind (ToM) is an aspect of social cognition which refers in part to the capacity to perceive and understand other people’s mental state. Deficits in these mentalizing processes ...are commonly observed in both schizophrenia and Autism Spectrum Disorder (ASD), and are thus evident in disorders with very different symptoms and clinical presentations. The aim of this study was to conduct a meta-analysis of all published data examining ToM deficits in schizophrenia and autism in order to determine whether these two disorders have distinct deficit profiles across multiple domains of ToM. We additionally aimed to explore the relationship between clinical symptoms and phase of illness on ToM deficits in schizophrenia.
Methods:
A literature search identified 74 eligible studies in schizophrenia involving 3555 cases and 22 studies in ASD involving 810 cases, as of August 2016. Meta-analyses were conducted to calculate the pooled effect size of deficits for each patient group in each ToM domain.
Results:
As expected, significant theory of mind deficits were observed in both schizophrenia and ASD. Strikingly, the most significantly impaired ToM domain in schizophrenia was understanding verbal intention (g = −1.33) followed by indirect speech (g = −1.09), second-order false belief (g = −0.89), faux-pas −0.88), emotional ToM (g = −0.76) and first-order false belief (g = −0.61). Understanding visual intention was not significantly impaired. In ASD, the most impaired domain was understanding indirect speech (g = −1.40), followed by faux-pas (g = −1.27), emotional ToM (g = −0.75), and understanding false belief (g = −0.467). Intention inferencing was not significantly impaired in ASD (g = −0.01). Planned meta-regression analyses revealed that positive symptoms significantly modulated the magnitude of deficit across several ToM domains in schizophrenia.
Conclusion:
Common symptoms of schizophrenia, such as paranoia and persecutory ideas, chime with the greatest observed ToM deficit observed here, which was understanding verbal intention, which was not impaired in ASD. Conversely, understanding meaning in speech was most impaired in ASD, but this was less impaired in schizophrenia. This study reveals that schizophrenia and ASD populations have distinct ToM deficit profiles. Understanding differences in ToM deficit profiles can help differentiate the clinical phenotypes of these disorders in a way that might enhance the identification of disorder-specific behavioral markers and the development of explanatory models and new treatments.
Background:
Lack of insight is common in patients with schizophrenia and a large number of studies have endeavored to clarify the relationship between level of insight and degree of clinical ...symptomatology. This study aimed to advance our understanding of this relationship by conducting an up-to-date meta-analysis of all relevant studies published to date.
Methods:
A literature search identified 151 eligible studies published up to August 2016 which together included 20 515 patients with schizophrenia. The statistical associations between insight, its sub-components, and clinical symptoms were analyzed to calculate pooled effects from all studies included. Additional planned analyses included examination of whether clinical, procedural, or demographic variables moderated the strength of these relationships.
Results:
Results revealed significant negative associations between global insight and positive (ES = −.27), negative (ES = −.22) and global (ES = −.28), symptoms; and a significant though weaker association with depressive symptoms (ES = .20; all
P
< .001). In terms of individual symptoms, insight held the strongest and most negative association with Unusual Thought Content (
r
= −.46,
P
< .001) and disorganization (
r
= −.38,
P
< .001). There was substantial variation in the strength of association between individual components of insight and symptoms. Meta-regression analyses revealed that illness duration, number of psychotic episodes, age, and age of onset significantly influences the strength of the relationship between insight and symptoms. Stage of illness, assessment scale, and rater (patient vs. clinician) also moderate these relationships.
Conclusion:
This study supports the general notion that insight and psychopathology are significantly associated in patients with schizophrenia, however, as the magnitude of associations are generally low to medium, overall findings suggest insight is largely independent from symptomatology. Results are of relevance to both clinical practice and future research studies.
Cognitive deficits, particularly in processing speed, are widely recognized as a critical feature of schizophrenia, and are also present across schizophrenia spectrum disorders. A number of important ...confounders, however, such as hospitalization effects and antipsychotic medication, have been shown to affect processing speed, causing debate as to the core cognitive deficits of schizophrenia. The study of individuals who are not clinically psychotic but have schizotypal traits allows investigation of cognitive deficits associated with both positive and negative schizotypy dimensions while excluding potential confounds.
A population-based community sample of 242 healthy adult volunteers assessed using the Structured Interview of Schizotypy – Revised (SIS-R) scale, and a neuropsychological testing battery that included measures of verbal ability, visual and verbal memory, verbal fluency, working memory, executive functions and processing speed. Participants were classified in High or Low Positive Schizotypy (H-PST or L-PST), High or Low Paranoia-like traits (H-PAR or L-PAR) and High or Low Negative Schizotypy (H-NST or L-NST) groups, respectively.
Individuals with H-PST performed significantly (p < 0.05) worse than L-PST on measures of processing speed and executive functions. Processing speed deficits were also observed in individuals with H-PAR compared to L-PAR (p < 0.05). There were no statistically significant differences in neuropsychological performance between H-NST and L-NST on any measure.
In a population-based community sample, individuals with high positive schizotypal traits or paranoia-like traits show impairments in processing speed. Consistent with a dimensional view of psychosis, this supports the hypothesis that processing speed represents a core deficit of schizophrenia-like mental states.
Social decision-making is fundamental for successful functioning and can be affected in psychiatric illness and by serotoninergic modulation. The Prisoner's Dilemma is the archetypal paradigm to ...model cooperation and trust. However, the effect of serotonergic enhancement is poorly characterized, and its influence on the effect of variations in opponent behavior unknown. To address this, we conducted a study investigating how the serotonergic enhancer 3,4-methylenedioxy-methamphetamine (MDMA) modulates behavior and its neural correlates during an iterated Prisoner's Dilemma with both trustworthy and untrustworthy opponents. We administered 100 mg MDMA or placebo to 20 male participants in a double-blind, placebo-controlled, crossover study. While being scanned, participants played repeated rounds with opponents who differed in levels of cooperation. On each round, participants chose to compete or cooperate and were asked to rate their trust in the other player. Cooperation with trustworthy, but not untrustworthy, opponents was enhanced following MDMA but not placebo (respectively: odds ratio = 2.01; 95% CI, 1.42-2.84,
< 0.001; odds ratio = 1.37; 95% CI, 0.78-2.30, not significant). Specifically, MDMA enhanced recovery from, but not the impact of, breaches in cooperation. During trial outcome, MDMA increased activation of four clusters incorporating precentral and supramarginal gyri, superior temporal cortex, central operculum/posterior insula, and supplementary motor area. There was a treatment × opponent interaction in right anterior insula and dorsal caudate. Trust ratings did not change across treatment sessions. MDMA increased cooperative behavior when playing trustworthy opponents. Underlying this was a change in brain activity of regions linked to social cognition. Our findings highlight the context-specific nature of MDMA's effect on social decision-making.
We provide a detailed analysis of the effect of 3,4-methylenedioxy-methamphetamine (MDMA) on cooperative behavior during interpersonal interactions, as well as the neural correlates underlying these effects. We find that, following administration of MDMA, participants behave more cooperatively, but only when interacting with trustworthy partners. While breaches of trustworthy behavior have a similar impact following administration of MDMA compared with placebo, MDMA facilitates a greater recovery from these breaches of trust. Underlying this altered behavior are changes in brain activity during the viewing of opponents' behavior in regions whose involvement in social processing is well established. This work provides new insights into the impact of MDMA on social interactions, emphasizing the important role of the behavior of others toward us.
Background: Poor insight in schizophrenia has been linked to poor cognitive functioning, psychological processes such as denial, or more recently with impaired metacognitive capacity. Few studies, ...however, have investigated the potential co-dependency of multiple factors in determining level of insight, but such a model is necessary in order to account for patients with good cognitive functioning who have very poor awareness. As evidence suggests that set-shifting and cognitive insight (self-reflection (SR) and self-certainty) are strong predictors of awareness we proposed that these factors are key mediators in the relationship between cognition and awareness. We hypothesised that deficits specifically in SR and set-shifting determine level of awareness in the context of good cognition. Methods: Thirty schizophrenia patients were stratified by high and low awareness of illness and executive functioning scores. Cognitive insight, cognition, mood and symptom measures were compared between sub-groups. Results: A low insight/high executive functioning (LI-HE) group, a high insight/high executive functioning (HI-HE) group and a low insight/low executive functioning (LI-LE) group were revealed. As anticipated, the LI-HE patients showed significantly lower capacity for SR and set-shifting than the HI-HE patients. Conclusions: This study indicates that good cognitive functioning is necessary but not sufficient for good awareness; good awareness specifically demands preserved capacity to self-reflect and shift-set. Results support Nelson and Narens' 1990. Metamemory: A theoretical framework and new findings. The Psychology of Learning and Motivation, 26, 125-173 model of metacognition by which awareness is founded on control (set-shifting) and monitoring (SR) processes. These specific factors could be targeted to improve insight in patients with otherwise unimpaired cognitive function.
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