Visual-spatial processing and working-memory load as a function of negative and positive psychotic-like experiences.

INTRODUCTION: Patients with schizophrenia show impairments in working-memory and visual-spatial processing, but little is known about the dynamic interplay between the two. To provide insight into this important question, we examined the effect of positive and negative symptom expressions in healthy adults on perceptual processing while concurrently performing a working-memory task that requires the allocations of various degrees of cognitive resources. METHODS: The effect of positive and negative symptom expressions in healthy adults (N = 91) on perceptual processing was examined in a dual-task paradigm of visual-spatial working memory (VSWM) under three conditions of cognitive load: a baseline condition (with no concurrent working-memory demand), a low VSWM load condition, and a high VSWM load condition. RESULTS: Participants overall performed more efficiently (i.e., faster) with increasing cognitive load. This facilitation in performance was unrelated to symptom expressions. However, participants with high-negative, low-positive symptom expressions were less accurate in the low VSWM condition compared to the baseline and the high VSWM load conditions. CONCLUSIONS: Attenuated, subclinical expressions of psychosis affect cognitive performance that is impaired in schizophrenia. The "resource limitations hypothesis" may explain the performance of the participants with high-negative symptom expressions. The dual-task of visual-spatial processing and working memory may be beneficial to assessing the cognitive phenotype of individuals with high risk for schizophrenia spectrum disorders.

The role of oxytocin in empathy to the pain of conflictual out-group members among patients with schizophrenia.

BACKGROUND: Oxytocin (OT) is associated with our ability to empathize and has been shown to play a major role in mediating social behaviors within the context of intergroup dynamics. Schizophrenia is associated with impaired empathy, and with a dysfunctional oxytocinergic system. The effect of OT on the empathic responses of patients with schizophrenia within the context of intergroup relationships has not been studied. The present study examined the effect of OT on the patients' empathic responses to pain experienced by in-group, conflictual out-group and neutral out-group members. METHOD: In a double-blind, placebo-controlled, within-subject cross-over design, the responses on the Pain Evaluation Task of 28 male patients with schizophrenia were compared to 27 healthy male controls. All participants received a single intranasal dose of 24 IU OT or placebo, 1 week apart. RESULTS: OT induced an empathy bias in the healthy controls towards the conflictual out-group members. Although this effect was absent in the patient group, OT seems to heighten an empathic bias in the patient group towards the in-group members when rating non-painful stimuli. CONCLUSIONS: The study demonstrates that the administration of OT can result in empathic bias towards adversary out-group members in healthy controls but not in patients with schizophrenia. However, the OT-induced bias in both the patients (in the no-pain condition towards the in-group members) and the healthy controls (in the no-pain and pain conditions towards the adversary out-group) suggests that OT enhances the distinction between conflictual in-group and out-group members.

The neurochemical hypothesis of 'theory of mind'.

This paper aims to explore the neurochemical basis of the ability to represent one's own or other's mental states such as intentions, beliefs, wants and knowledge, an ability often referred to as 'theory of mind'. Based on neurochemical and psychopharmacological investigations in autism and schizophrenia, pathologies in which this ability is impaired, it is hypothesized that 'theory of mind' abilities are contingent on the integrity of the serotonergic and dopaminergic system. This hypothesis is discussed in light of the system's neurochemical properties and role in cognition. It is suggested that specific abnormalities to this system can account for differences in the profile of 'theory of mind' impairments that may exist among patients belonging to different pathologies.

Indexical and symbolic referencing: what role do they play in children's success on theory of mind tasks?

Numerous measures have been employed in the last 17 years to assess theory of mind (ToM). The literature reports marked variability in the age at which children succeed on these measures. To account for this variability, researchers have provided explanations ranging from cognitive shifts and voids to the inability to understand the language of the tasks or to social/pragmatic considerations, all of which tell us little if anything about the internal mechanism underlying ToM. The main purpose of this paper is to provide a comprehensive theoretical account of children's success and the discrepancies found across different ToM tasks. We test the hypothesis that children's understanding of ToM is sensitive to the basic elements of language, that is, to whether the language is indexical or symbolic. Support for this account was found in the analysis of selected test protocols in four published studies of ToM, and new data collected from 53 children (4--6 years) which showed that a higher percentage of children succeeded on tasks with a high ratio of indexical to symbolic references than on tasks with a high ratio of symbolic to indexical references. There was also a main effect of age with older children succeeding at higher rates on both tasks than younger children. Our findings suggest that indexical representation can afford ToM understanding in 4-year-olds, but is not sufficient for a more mature ToM. The latter requires symbolic representation that was demonstrated by the majority of 5--6-year-olds.

Childhood schizophrenia: responsiveness to questions during conversation.

OBJECTIVES: This study characterized further the communicative deficits associated with childhood-onset schizophrenia. It examined the use of speech functions that involve responses to Yes/No and Wh- questions in children with schizophrenia and normal children during conversation. It also ascertained the relationship of these speech functions with cognition and thought disorder. METHOD: Speech function variables, formal thought disorder, and cohesion were coded in 32 schizophrenic and 34 normal children, aged 5.6 to 12.4 years, from speech samples elicited with the Story Game. RESULTS: The schizophrenic children were significantly more impaired in the use of speech functions than the normal children. Other than the association of a subset of the speech functions with distractibility and loose associations, the speech function measures were unrelated to cognitive and thought disorder measures. CONCLUSIONS: Speech function analysis detects communication deficits not captured by thought disorder measures in children with schizophrenia.

Phoricity as a measure of Clozaril's efficacy in treating disorganized schizophrenia.

The current study investigated the use of cohesive links analysis as a measure of Clozaril's efficacy in treating disorganized schizophrenia. Two adolescent patients with disorganized schizophrenia, and a comparison group of adolescents with no reported history of psychiatric disturbances, were engaged in the study. All participants were engaged by an examiner in 20-minute conversations that touched on various topics. The conversations were audiotaped, transcribed, and coded blindly for several types of cohesive links. Certain changes in the conversational ability of individuals with schizophrenia were observed following the introduction of Clozaril. For example, the use of anaphoric references became more similar to that of the comparison group. No change was observed, however,in the use of unclear references. Cohesion variables were found to be sensitive to changes in the patients' psychiatric state. The results support further investigation of stimulant effects on discourse in adolescents with disorganized schizophrenia

A study of cohesive patterns and dynamic choices utilized by two schizophrenic patients in dialog, pre- and post-medication.

The present study evaluated the communicative deficits in the linguistic performance of two Arabic speaking schizophrenics having a first episode of disorganized schizophrenia. Two facets of the conversational performance of each patient prior to and following antipsychotic medication treatment were considered and compared to normals' performance of these two measures. These were the dynamic development of the interviews and selected cohesive devices. A description of the patients' aberrant conversational behavior and deficits in terms of systemic grammar is offered for profiling schizophrenics' discourse and measuring the effects of stimulant treatment. The neuroleptic clozapine led to both positive and negative changes in the socially appropriate use of language in the schizophrenics' conversations.