Jordi E. Obiols

Neurocognitive, behavioural and neurodevelopmental correlates of schizotypy clusters in adolescents from the general population

Abstract Introduction : Studies on the neurocognitive correlates of schizotypy dimensions have found inconsistent results. This might stem from the fact that correlational methods, in contrast to cluster analysis, do not account for the possibility that a subject presents high scores on more than one dimension simultaneously. We aimed to establish clusters of normal adolescents based on schizotypy dimensions and compare them on neurocognitive, behavioural, and neurodevelopmental markers. Methods : Two hundred seventy normal adolescents from the general population (mean age 13.4, SD=0.72) attending obligatory education were evaluated. Results : A K-means iterative cluster analysis was performed with the Perceptual Aberration, Revised Social Anhedonia and Physical Anhedonia Scales. A forced four-cluster model yielded the following clusters: ‘negative schizotypy’, ‘high or mixed schizotypy’, ‘positive schizotypy’, and ‘normal scorers’. Comparisons with ANOVAs showed that ‘high schizotypes’ performed poorly on neurocognition (Wechsler Intelligence Scales for Children-Revised (WISC-R) and Verbal Fluency (FAS)) and obtained the highest teacher ratings (TRF) of behavioural problems. ‘Negative schizotypes’ had the worst WCST results and more dermatoglyphic abnormalities. Both clusters had more neurological soft signs than ‘normal scorers’ and ‘positive schizotypes’. Conclusions : Our results with community adolescents found the same cluster structure than the previous cluster analytic studies conducted in adult college subjects. Furthermore, we showed differences among them on neurocognitive and malneurodevelopment markers consistent with the adult literature on schizotypy.

Theory of mind deficits in chronic schizophrenia: Evidence for state dependence

There is evidence that people with schizophrenia show specific deficits in theory of mind (ToM). However, it is a matter of debate whether these are trait or state dependent, and the nature of the relationship between ToM deficits and particular symptoms is controversial. This study aimed to shed further light on these issues by (1) examining ToM abilities in 61 individuals with chronic schizophrenia during a stable phase as compared with 51 healthy controls matched by gender, age, educational level and current IQ, and (2) exploring the relationship between ToM and symptoms. Second order verbal stories and a non-verbal picture-sequencing task were used as ToM measures. Results showed no differences in ToM performance between patients and controls on either measure. Subsequent subgrouping of patients into remitted and non-remitted showed a worse performance of non-remitted patients only on second order ToM tasks. Specific ToM deficits were found associated with delusions. Association with negative symptoms was found to be less specific and accounted for by illness chronicity and general cognitive impairment. The results from the present study are in line with models which hypothesise that specific ToM deficits in schizophrenia are state dependent and associated with delusions. Such associations may also be task specific.

Psychometric schizotypy and sustained attention in young males

A sample of 343 young males in military duties were studied by means of two schizotypy scales (Claridges STA and Chapmans PAS). A psychosis-prone group (n = 35) was compared with a control group on a standard sustained attention task, the Continuous Performance Task (CPT, identical pairs version). The expected association between high schizotypy scores and low CPT performance was confirmed by our results. These findings add evidence to the view supported from high-risk research and attention research with schizophrenics, that subtle attention deficits are present among schizophrenia spectrum subjects. We also discuss the role of state anxiety as a possible nuisance variable.

Neurological soft signs in adolescents with poor performance on the continuous performance test: markers of liability for schizophrenia spectrum disorders?

Abstract There is much evidence that neurological soft signs (NSS) are highly prevalent in both adults and children with schizophrenia. In addition, they have been detected as early precursors of a schizophrenic outcome in at-risk subjects. Such findings point to the possible value of NSS as neurointegrative markers in schizophrenia which has been hypothesized to be a neurodevelopmental disease. In our study we used a biobehavioral criterion to select the ‘at-risk’ group, a sustained attentional deficit as measured by the continuous performance test (CPT). We compared 140 normal adolescents with 162 ‘CPT-linked vulnerable’ adolescents (index subjects) on a battery for the assessment of NSS (including laterality), IQ, frontal lobe function and schizotypy. An association was found between NSS and attentional deficit. Furthermore, index subjects with NSS were characterized by lower IQ scores, poorer performance on frontal lobe tests and greater problems with social interaction. There was also a trend for an association between male sex and both left-handedness and NSS.

Developmental instability and schizotypy

INTRODUCTION It has been suggested that evidence of developmental disturbance of cognition and lateralisation in schizophrenia can be best understood from the perspective of developmental stability (DS), an indicator of the extent to which an individual develops according to a specified ontogenic programme in the presence of environmental noise. Higher levels of fluctuating asymmetry (FA; the difference between right and left side of a quantitative morphological trait such as dermatoglyphics) are thought to reflect less DS. We examined this issue for dimensions of schizotypy. METHODS Associations between FA, measures of laterality and cognitive function on the one hand, and negative and positive dimensions of schizotypy on the other, were examined in a sample of 260 healthy adolescents aged 11.9-15.6years. FA was measured as a-b ridge count right-left differences. Neuropsychological measures yielded a general cognitive ability score and a frontal function score. Laterality was assessed with the Annett scale. RESULTS Measures of psychosis proneness were normally distributed. Negative schizotypy was associated with more FA and lower general cognitive ability in a dose-response fashion. The association with FA was more apparent in boys. No associations existed with laterality or frontal function. CONCLUSION The negative dimension of schizotypy may be associated with early developmental instability, resembling the pattern seen in the negative symptom dimension of schizophrenia. Measures of fluctuating asymmetry may be more sensitive with regard to the schizotypy phenotype than measures of laterality.

Gender differences in individuals at high-risk of psychosis: a comprehensive literature review.

Introduction. To date, few studies have focused on the characterization of clinical phenomenology regarding gender in population at high-risk of psychosis. This paper is an attempt to summarize the findings found in the scientific literature regarding gender differences in high-risk populations, taking into account parameters studied in populations with schizophrenia and other psychotic disorders, such as incidence, clinical expression, duration of untreated illness (DUI), social functioning, and cognitive impairment prior to full-blown psychosis development. Method. Studies were systematically searched in PubMed. Studies using gender variable as a control variable were excluded. 12 studies met inclusion criteria. Results. Most of the studies found a differential pattern between women and men as regards clinical, social, and cognitive variables in the prodromal phase, with worse performance in men except in cognitive functioning (more severe negative symptoms, worse social functioning, and longer DUI in men). Similar conversion rates over time were found between men and women. Conclusions. Many of the studies analyzed suggest that differences between men and women in the expression of psychosis extend across a continuum, from the subclinical forms of illness to the debut of psychosis. However, the small number of studies and their significant methodological and clinical limitations do not allow for firm conclusions.

ADHD Predominantly Inattentive Subtype With High Sluggish Cognitive Tempo: A New Clinical Entity?

Objective: The authors investigate differences in the neuropsychological and behavioral profiles of two groups of children with ADHD, one with predominantly inattentive subtype of ADHD (PI) and high sluggish cognitive tempo (SCT; n = 19) and another formed by the rest of the sample (children with ADHD combined subtype and children with PI and low SCT scores; n = 68). Method: Instruments included Wechsler Intelligence Scale for Children and subtests from Developmental Neuropsychological Assessment, Conners’ Continuous Performance Test, Behavior Rating Inventory of Executive Function, and Achenbach’s Child Behavior Checklist for ages 6 to 18. Results: PI with high SCT had fewer problems with sustained attention, and more internalizing problems, anxiety/depression, and withdrawn/depressed behavior, and more executive problems with self-monitoring than the rest of the ADHD sample. Conclusion: This study supports revising subtype’s criteria and further studying the hypothesis that ADHD with high SCT constitutes a separate clinical entity.

Exploratory study of the association between insight and Theory of Mind (ToM) in stable schizophrenia patients

Background. Poor insight and impairment in Theory of Mind (ToM) reasoning are common in schizophrenia, predicting poorer clinical and functional outcomes. The present study aimed to explore the relationship between these phenomena. Methods. 61 individuals with a DSM-IV diagnosis of schizophrenia during a stable phase were included. ToM was assessed using a picture sequencing task developed by Langdon and Coltheart (1999), and insight with the Scale to Assess Unawareness of Mental Disorder (SUMD; Amador et al., 1993). Multivariate linear regression analysis was carried out to estimate the predictive value of insight on ToM, taking into account several possible confounders and interaction variables. Results. No direct significant associations were found between any of the insight dimensions and ToM using bivariate analysis. However, a significant linear regression model which explained 48% of the variance in ToM was revealed in the multivariate analysis. This included the 5 insight dimensions and 3 interaction variables. Misattribution of symptoms—in aware patients with age at onset >20 years—and unawareness of need for medication—in patients with GAF >60—were significantly predictive of better ToM. Conclusion. Insight and ToM are two complex and distinct phenomena in schizophrenia. Relationships between them are mediated by psychosocial, clinical, and neurocognitive variables. Intact ToM may be a prerequisite for aware patients to attribute their symptoms to causes other than mental illness, which could in turn be associated with denial of need for medication.

Sustained attention deficit in young schizophrenic and schizotypic men.

We studied groups of 39 schizophrenic subjects, 35 schizotypic subjects, and 33 control subjects, comparing them on a standard sustained attention task called the Continuous Performance Test (identical pairs version). The expected negative relationship between performance on sustained attention and psychopathology was confirmed by differences among the three groups which were in the direction predicted, although only the difference between the schizophrenic group and the other two groups was significant. This finding adds evidence to the view from research on high risk and attention with schizophrenic subjects that subtle attention deficits are present among subjects within the schizophrenia spectrum. Consequently, our results can be understood as supporting a dimensional theory of psychopathology.

Abdominal pain in British young people: Associations, impairment and health care use

OBJECTIVE To assess the frequency and associations of abdominal pain in a sample of British secondary school young people and to examine predictors of impairment and health care use. METHODS Cross-sectional study of young people aged 11-16 years that completed questionnaires documenting abdominal pain, related impairment and health care consultations. They also provided information detailing other physical symptoms, health problems and mental health status. RESULTS 1173 students completed questionnaires; 598 (53%) reported abdominal pains in the previous 3 months (15% >once a week). Pains were significantly linked to reporting medical illness, to high levels of a broad range of physical symptoms and with students deeming these symptoms to be stress/mood sensitive. They were also linked to depressive and other emotional and behavioural problems and with medical help seeking (seeing a health professional in the previous year and contact ever with mental health practitioners). Considerable impairment was reported by 36%; this was independently predicted by abdominal pain frequency, higher levels of concurrent physical symptoms and symptom stress/mood sensitivity. In 18% of students the abdominal pains had led to medical consultations; this was independently predicted by pain related impairment. CONCLUSIONS Frequent abdominal pains are common in British secondary school adolescents; they are linked to emotional symptoms and are often impairing and lead to medical consultations. Impairment was associated not only to pain frequency but also to reporting other physical symptoms and symptom stress/mood sensitivity, and impairment was a strong predictor of medical help seeking.