Schizophrenia, dissociation, and consciousness

Current thinking suggests that dissociation could be a significant comorbid diagnosis in a proportion of schizophrenic patients with a history of trauma. This potentially may explain the term “schizophrenia” in its original definition by Bleuler, as influenced by his clinical experience and personal view. Additionally, recent findings suggest a partial overlap between dissociative symptoms and the positive symptoms of schizophrenia, which could be explained by inhibitory deficits. In this context, the process of dissociation could serve as an important conceptual framework for understanding schizophrenia, which is supported by current neuroimaging studies and research of corollary discharges. These data indicate that the original conception of “split mind” may be relevant in an updated context. Finally, recent data suggest that the phenomenal aspects of dissociation and conscious disintegration could be related to underlying disruptions of connectivity patterns and neural integration.     

The dreaming brain/mind, consciousness and psychosis

Several independent lines of research in neurobiology seem to support the phenomenologically-grounded view of the dreaming brain/mind as a useful model for psychosis. Hallucinatory phenomena and thought disorders found in psychosis share several peculiarities with dreaming, where internally generated, vivid sensorimotor imagery along with often heightened and incongruous emotion are paired with a decrease in ego functions which ultimately leads to a severe impairment in reality testing. Contemporary conceptualizations of severe mental disorders view psychosis as one psychopathological dimension that may be found across several diagnostic categories. Some experimental data have shown cognitive bizarreness to be equally elevated in dreams and in the waking cognition of acutely psychotic subjects and in patients treated with pro-dopaminergic drugs, independent of the underlying disorder. Further studies into the neurofunctional underpinnings of both conditions will help to clarify the use and validity of this model.     

Understanding the executive functioning heterogeneity in schizophrenia

Schizophrenia is characterized by heterogeneous brain abnormalities involving cerebral regions implied in the executive functioning. The dysexecutive syndrome is one of the most prominent and functionally cognitive features of schizophrenia. Nevertheless, it is not clear to what extend executive deficits are heterogeneous in schizophrenia patients. Furthermore, it is still unknown if the executive impairments observed in schizophrenia are better characterized as specific or as reflecting generalized cognitive factors. The four executive processes (i.e. updating, inhibition, shifting and divided attention) described in Miyake et al.'s (2000) theoretical model were examined in 62 individuals with schizophrenia and 49 healthy controls. At group level, impairments in all four executive processes confirmed the marked impairment in executive functioning in patients with schizophrenia. Statistical analysis indicated that executive performances in schizophrenia patients were more heterogeneous than in healthy controls. Compared with standardized norms, 94% of patients exhibited impairment in at least one of the executive tasks. Twenty-one percent of patients exhibited impairment in one executive task, 27% in two tasks, 23% in three executive tasks and 23% exhibited impairments in the four executive tasks. Six percent of patients had normal executive profile. Regression analysis indicated that only premorbid intellectual quotient and a general slowing in processing speed predicted the executive dysfunction severity. Executive functioning was not affected by age, duration of illness, psychotic status, or by antipsychotic dosage. Our results emphasize the heterogeneity of the dysexecutive syndrome in schizophrenia when individual profile analysis is considered, and extend the view that individual cognitive differences in schizophrenia are largely underlined by general cognitive factors such as intellectual level and general processing speed.     

The criminal and personality profile of patients with schizophrenia and comorbid psychopathic traits

Sixty-one male forensic patients who met the DSM-IV criteria for schizophrenia were categorised into high and low psychopathic trait groups using the Psychopathy Checklist: Screening Version. The groups were compared on their criminal history, symptom profile, personality style, risk scores and subsequent institutional violence. Patients with high scores on the PCL:SV had a greater number of previous convictions and were more likely to have a family history of criminality. The high psychopathy-scoring group had higher levels of Positive and Negative Syndrome Scale grandiose and hostile symptomatology, and higher scores on trait impulsivity and aggression. They also had a more coercive, less compliant interpersonal style than the low-psychopathy scoring group. The high-psychopathy scoring group were more likely to be involved in institutional aggression and had higher levels of risk for violence. Patients with schizophrenia and high levels of comorbid psychopathy have a distinctive interpersonal style that may contribute to their greater risk of disruptive institutional behaviour.     

Attachment theory: a framework for understanding symptoms and interpersonal relationships in psychosis

We investigated associations between adult attachment, symptoms and interpersonal functioning, including therapeutic relationships in 96 patients with psychosis. Using a prospective design, we also assessed changes in attachment in both psychiatrically unstable and stable groups. We measured attachment using the Psychosis Attachment Measure (PAM) and interpersonal problems and therapeutic relationships were assessed from both psychiatric staff and patient perspectives. Avoidant attachment was associated with positive symptoms, negative symptoms and paranoia. Attachment ratings were relatively stable over time, although changes in attachment anxiety were positively correlated with changes in symptoms. Predicted associations between high levels of attachment anxiety and avoidance and interpersonal problems were supported, and attachment avoidance was associated with difficulties in therapeutic relationships. Findings suggest that adult attachment style is a meaningful individual difference variable in people with psychosis and may be an important predictor of symptoms, interpersonal problems and difficulties in therapeutic relationships over and above severity of illness.     

Schizotypy, taxometrics, and disconfirming theories in soft science: Comment on

Among the most consistently replicated findings in literature addressing the latent structure of psychopathology is evidence for a discrete latent class of individuals who are vulnerable to schizophrenia (schizotypes). Rawlings, Williams, Haslam, and Claridge (2008) challenge these findings by subjecting schizotypy scale scores to taxometric analysis, using a data simulation technique to accommodate variable skew. The authors conclude that schizotypy reflects a latent dimension, and that evidence for discrete latent structure from previous studies is likely an artifact of skewed variables. In this comment, we discuss (a) the philosophical implications of disconfirming well replicated findings in soft science with a single study, (b) important considerations when defining the schizotypy construct, (c) intricacies in executing and interpreting a taxometric analysis, and (d) problems with drawing strong conclusions from null results. Considerable evidence suggests that schizotypy is a discrete latent class, a conclusion that is unlikely the result of skewed variables.     

Schizotypal personality traits and prediction of one's own movements in motor control: what causes an abnormal sense of agency?

Background. Positive schizophrenic symptoms, especially passivity phenomena, including auditory hallucinations, may be caused by an abnormal sense of agency, which people with schizotypal personality traits also tend to exhibit. A sense of agency asserts that it is oneself who is causing or generating an action. It is possible that this abnormal sense of self-agency is attributable to the abnormal prediction of one’s own movements in motor control. Method. We conducted an experiment using the “disappeared cursor” paradigm in which non-clinical, healthy participants were required to click on a target using an invisible mouse cursor. Prediction error was defined as the distance between the target and the click point. Results. The results showed that schizotypal personality traits, but not depressive or anxious traits, were correlated with deficits in predicting movements of the subjects’ left hand. In particular, auditory hallucination proneness had the strongest relationship with movement prediction error. In this report, we also discuss the error tendency (overestimations or underestimations of one’s own movements). Conclusions. This finding is in accordance with the idea that passivity phenomena or proneness may be caused by the abnormal prediction of one’s own actions or movements.     

Narrative accounts of illness in schizophrenia: association of different forms of awareness with neurocognition and social function over time

Awareness of illness in schizophrenia reflects complex storied understanding of the impact of the disorder upon one’s life. Individuals may be aware of their illness in different ways and this may be related to their functioning. A total of 76 adults with schizophrenia were assessed for their awareness of illness, neurocognition, social cognition, and social function concurrently and social function was also assessed at three later time points. A cluster analysis revealed 3 groups: generally full awareness, generally limited awareness, and superficial awareness. Comparisons between these profiles revealed the superficial group had poorer executive function, emotion recognition ability, and capacity for social relationships than the full awareness group, yet had better verbal memory and more social contacts than the limited awareness group. These results suggest assessing the narrative qualities of awareness of illness may reveal unique links with cognition and function, and this may have implications for interventions.     

Is there an evolutionary advantage of schizophrenia?

Schizophrenia is a universal disorder with strongly genetic aetiology. A constant prevalence rate, universally, in the face of reduced fecundity leads to the argument here that an evolutionary advantage exists, but not solely for schizophrenia. Possible areas of advantage are examined and it is argued that schizophrenia exists as a costly trade-off, in the evolution of Homo sapiens, as a by-product of a yet unknown uniquely human quality. The reason it has stayed in existence is due to a combination of advantages bestowed upon the kin, the group and, to a lesser extent, individuals who suffer from the disorder; these all contribute a different type of advantage, each of which alone would not be sufficient. Further, the evidence for the other advantages alone lack the rigour of evidence seen in the by-product theories, which provide as yet unparalleled comprehensive evolutionary evidence.