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Population variation in handedness (a correlate of cerebral dominance for language) is in part genetic and, it has been suggested, its persistence represents a balanced polymorphism with respect to cognitive ability. This hypothesis was tested in a sample of 12,770 individuals in a UK national cohort (the National Child Development Study) by assessing relative hand skill (in a square checking task) as a predictor of verbal, non-verbal, and mathematical ability and reading comprehension at the age of 11 years. Whereas some modest decrements were present in extreme right handers the most substantial deficits in ability were seen close to the point of equal hand skill (“hemispheric indecision”). For verbal ability females performed better than males, but the relationship to relative hand skill was closely similar for the two sexes; for reading comprehension males close to the point of equal hand skill showed greater impairments than females. Analysed by writing hand the relationship of ability to hand skill appeared symmetrical about the point of “hemispheric indecision”. The variation associated with degrees of dominance may reflect the operation of continuing selection on the gene (postulated to be X-Y linked) by which language evolved and speciation occurred.

Background: Less syntactically complex speech in patients with schizophrenia has been thought to represent a premorbid dysfunction, of possible prognostic value and indicative of a neurodevelopmental origin for schizophrenia.Method: Narratives written at age 11 by children who then developed psychiatric disorders in adult life (using PSE CATEGO diagnoses), especially schizophrenia, were compared with matched controls on syntactic complexity, syntactic maturity, grammatical deviance and spelling ability.Results: Children who later developed either schizophrenia, affective psychosis or a neurotic type of disorder in adulthood did not differ from normal controls on any of the measures of syntactic production, grammatical errors or spelling.Conclusions: It is probable that previous reports of reduced syntactic complexity in schizophrenic speech are a consequence of being in a psychotic state and do not represent a premorbid deficit. [ABSTRACT FROM AUTHOR]

Background: This exploratory study seeks to generate new hypotheses about the relationship between obstetric complications and schizophrenia.Method: The British Perinatal Mortality Survey represents 98% of all births during one week in March 1958 in Great Britain. Present State Examination (PSE), Catego diagnoses of narrowly defined schizophrenia (n = 49), broadly defined schizophrenia (n = 79), affective psychosis (n = 44) and neurosis (n = 93) were derived from case notes for all cohort members. The remainder of the cohort, surviving the perinatal period, acted as controls (n = 16 812). Variables in the British Perinatal Mortality Survey were grouped into five categories: the physique/lifestyle of the mother (including demographic characteristics), her obstetric history, the current pregnancy, the delivery and the condition of the baby.Results: There were 7/17 significant differences in maternal physique/lifestyle and obstetric history between the births of schizophrenics and controls, compared to 4/40 comparisons of somatic variables relating to pregnancy, birth and the condition of the baby. This compares with 4/17 and 7/40 for affective psychotics and a total of 4/57 differences for all categories of variables when neurotics were contrasted with controls.Conclusions: The purported increased risk of obstetric complications in schizophrenics may result from the physique/lifestyle of their mothers. [ABSTRACT FROM AUTHOR]

A response by D.J. Done and A. Sacker to a letter to the editor about their article "Antecedents of schizophrenia and affective illness: obstetric complications" in a 1995 issue is presented.

A response by S.J. Leask and colleagues to a letter to the editor about their article "No association between breastfeeding and adult psychosis in two national birth cohorts" in volume 177 is presented.

This study evaluates whether patients with schizophrenia have a degraded memory store for semantic knowledge. 20 patients with a chronic history of schizophrenia and evidence of cognitive impairment were selected, since the literature indicates that this subgroup is most likely to manifest a degraded semantic knowledge store. Their profile of semantic memory impairments was compared to that of a group of Alzheimer's Dementia (AD) patients (n=22), who met neuropsychological criteria for degraded semantic store. Both groups were matched for Performance IQ. 15 elderly healthy controls were also included in the study. The AD and schizophrenia groups produced substantially different profiles of semantic memory impairment. This is interpreted as indicating that the semantic impairments in this subgroup of patients with schizophrenia do not result from a degraded store. This is corroborated by an analysis of the data using other neuropsychological criteria for determining degraded store. We conclude that there is little evidence for a classic degradation of semantic knowledge in schizophrenia, and it appears that impairments result from an inability to use semantic knowledge appropriately, particularly when selection of salient semantic relations is required. [ABSTRACT FROM AUTHOR]

Introduction: Patients grouped by latent class analysis of symptoms show some consensus between studies, and may be less etiologically heterogeneous than current diagnoses. If so, the effect size of 'neurodevelopmental' risk factors may be greater than in equivalent DSMIV diagnostic groups., Method: Two hundred fifty six individuals with neurodevelopmental risk factors recorded in the National Child Development Study (1958) UK birth cohort were grouped by data-driven illness subtypes, derived previously in over 1000 individuals. The effect sizes of these risks were compared between data-derived and DSMIV schizophrenia (295.x) groups., Results: Compared to DSMIV schizophrenia, the data-driven subtype broadly characterized by the presence of psychotic symptoms in the absence of affective symptoms showed significantly greater effect sizes in eight out of thirteen continuously-rated risk factors: birth weight, cognition, childhood behavioural problems, and neurological softsigns including handedness., Conclusion: A data-driven subgroup of schizophrenia patients, characterized as lacking co-morbid depressive symptoms, is less heterogeneous with respect to neurodevelopmental etiology.

This study looks at the body image, mood and quality of life of a group of 36 young people aged between 11 and 19 years who had burns as children, compared with an age-matched control group of 41 young people who had not had these injuries. Participants completed the Body Esteem Scale (BES), the Satisfaction With Appearance Scale (SWAP), the Beck Depression Inventory-II (BDI-II) and the Youth Quality of Life Questionnaire (YQOL). It was hypothesised that young burn survivors would report more dissatisfaction with their appearance, a lower mood and a lower quality of life compared with non-injured controls. However, young burn survivors reported significantly more positive evaluations of how others view their appearance (p=0.018), more positive weight satisfaction (p=0.001) and a higher quality of life (p=0.005) than the control group. They also reported more positive general feelings about their appearance, although this was just below the level for statistical significance (p=0.067) and a similar mood to the school sample (p=0.824). The data suggest that young burn survivors appear to be coping well in comparison to their peers, and in some areas may be coping better, in spite of living with the physical, psychological and social consequences of burns.

Semantic memory impairments have been reported extensively in people with schizophrenia. Inefficient search and retrieval strategies, due to an executive dysfunction, rather than a primary loss of semantic knowledge are a primary candidate for such impairments. In order to test this hypothesis we compared the performance of 20 patients meeting DSM-IV-TR criteria for schizophrenia with that of 20 healthy controls and 10 patients with acquired brain injury (ABI) with a dysexecutive syndrome. Seventy percent of the people with schizophrenia and 100% of the ABI patients in this study met criteria for executive impairment. However, the two groups performed significantly differently on a range of semantic memory tests. Whereas 45% of the patients with schizophrenia met criteria for distorted semantic category boundaries (n.b. overinclusion), this was true for only 10% of the ABI patients. In addition, no correlation was found between severity of executive dysfunction and tendency to overinclude in the schizophrenia group. This pattern of neuropsychological findings suggests that overinclusion, or disorganized semantic categorization procedures, in schizophrenia does not result from a classical executive dysfunction. Alternative explanations are discussed.

Background: Disorganisation of semantic memory could provide a cognitive explanation for the disturbances of thinking and reasoning in schizophrenia. In this study, we directly test this explanation by identifying patients with disorganised semantic categories and then examine how they use their knowledge about these same categories in an inductive reasoning task., Method: Experiment 1 utilised a semantic category-sorting task to identify patients with disorganisation of semantic memory. In Experiment 2, the patients with disorganised categories carried out a category-based inductive reasoning task. Accurate performance on this task requires access to well-organised semantic knowledge about the objects and categories used in Experiment 1., Results: Patients with disorganised semantic categories in Experiment 1 did not demonstrate any difficulties or unusual responses when reasoning about the same categories in Experiment 2., Conclusion: Disorganisation of semantic memory may not be the primary cause of disturbed reasoning or thought in schizophrenia. Patients with schizophrenia tend to generate ad hoc categories, which are unsuited to the current context. Impaired performance on semantic memory tasks can arise from a misunderstanding of social context.

This paper describes a series of modular neural network simulations of visual object processing. In a departure from much previous work in this domain, the model described here comprises both supervised and unsupervised modules and processes real pictorial representations of items from different object categories. The unsupervised module carries out bottom-up encoding of visual stimuli, thereby developing a "perceptual" representation of each presented picture. The supervised component then classifies each perceptual representation according to a target semantic category. Model performance was assessed (1) during learning, (2) under generalisation to novel instances, and (3) after lesion damage at different stages of processing. Strong category effects were observed throughout the different experiments, with living things and musical instruments eliciting greater recognition failures relative to other categories. This pattern derives from within-category similarity effects at the level of perceptual representation and our data support the view that visual crowding can be a potentially important factor in the emergence of some category-specific impairments. The data also accord with the cascade model of object recognition, since increased competition between perceptual representations resulted in category-specific impairments even when the locus of damage was within the semantic component of the model. Some strengths and limitations of this modelling approach are discussed and the results are evaluated against some other accounts of category-specific recognition failure.

Given that certain types of semantic dysfunction in DAT have been attributed to difficulties in accessing visual knowledge, the issues of integrity of access to, and format of storage, within the "visual store" are particularly important. In these experiments, we tested 10 DAT patients and matched controls on the reality decision and part-whole matching tasks. Visual knowledge was found to be significantly impaired in the DAT group. Moreover, DAT patients displayed disproportionate deficits in accessing visual knowledge of items from nonliving categories. Results are interpreted within a framework of differential hierarchical access to visual representations of perceptually similar and perceptually distinct categories of items.

Population variation in handedness (a correlate of cerebral dominance for language) is in part genetic and, it has been suggested, its persistence represents a balanced polymorphism with respect to cognitive ability. This hypothesis was tested in a sample of 12,770 individuals in a UK national cohort (the National Child Development Study) by assessing relative hand skill (in a square checking task) as a predictor of verbal, non-verbal, and mathematical ability and reading comprehension at the age of 11 years. Whereas some modest decrements were present in extreme right handers the most substantial deficits in ability were seen close to the point of equal hand skill ('hemispheric indecision'). For verbal ability females performed better than males, but the relationship to relative hand skill was closely similar for the two sexes; for reading comprehension males close to the point of equal hand skill showed greater impairments than females. Analysed by writing hand the relationship of ability to hand skill appeared symmetrical about the point of 'hemispheric indecision'. The variation associated with degrees of dominance may reflect the operation of continuing selection on the gene (postulated to be X-Y linked) by which language evolved and speciation occurred.

The origins of schizophrenia are obscure. One suggestion is that it represents a component of the genetic variation associated with the establishment of dominance in one or other cerebral hemisphere, a mechanism that has been crucial in the evolution of language. Indices of cerebral hemispheric dominance (hand, foot and eye preference, speed of checking squares) recorded on the 16,980 children in the UK National Child Development Study cohort were examined in relation to psychiatric admission by the age of 28 years. Diagnoses were established by the application of Present State Examination criteria to case notes. Pre-schizophrenic children (n = 34-36) were more likely (p < 0.0003) to be rated by their mothers as ambidextrous at the age of 7 years, and at 11 years were less (p < 0.01) strongly right-handed than their peers in the cohort population on a test of relative hand skill: children who later developed affective psychosis (n = 25) or neurosis (n = 60) did not differ significantly from controls. Delay in establishing dominance in one hemisphere could be the critical factor that predisposes to schizophrenia.

In a small study of up to 3 years' duration comparison of the value of amitriptyline alone versus amitriptyline + lithium in unipolar cases (27 patients) and of that of lithium alone versus amitriptyline + lithium in bipolar cases (13 patients) showed no advantage for the combination treatments in terms of efficacy in reducing depressive relapses. There was no effect of treatment, developing depression or developing hypothyroidism upon the psychological tests which were conducted during this prolonged study. Observer and self ratings detected an increase in depression before relapse was clearly present, but of the various psychological assessments conducted only arousal showed changes in association with developing and definite relapse. The prescription of lithium but not amitriptyline + lithium or amitriptyline alone was associated with significant increases in blood pressure.

Schizophrenia-like psychoses occur more frequently than expected in patients with chronic temporal lobe epilepsy. We have analyzed pathological and clinical data from a series (n = 249) of temporal lobectomies to determine the factors that may relate to the development of schizophrenia-like psychosis. Schizophrenia-like psychoses did not occur at random; they were significantly associated with lesions that (1) originated in the fetus or perinatally, (2) affected neurons in the medial temporal lobe, and (3) gave an early age of first fit. Gangliogliomas--developmental lesions of the medial temporal lobe containing aberrant neurons--were disproportionately (p less than 0.001) associated with risk of psychosis. Schizophrenia-like psychoses arising preoperatively occurred more often (p = 0.1) with left-sided lesions. Asymmetry of lesion was not present in cases with postoperative psychoses. These findings are of interest in relation to recent studies suggesting that the structural abnormalities found in the brains of schizophrenics arise during fetal brain development.

A viable neuropsychology of schizophrenia requires, first, that signs and symptoms be understood in terms of underlying psychological processes and, second, that these underlying processes be related to brain systems. We propose that the negative signs of schizophrenia reflect a defect in the initiation of spontaneous action, while the positive symptoms reflect a defect in the internal monitoring of action. The spontaneous initiation of action depends upon brain systems linking the prefrontal cortex and the basal ganglia. Internal monitoring, carried out in the hippocampus, of spontaneous action, depends upon links between the prefrontal cortex and the hippocampus via the parahippocampal cortex and the cingulate cortex.

On each of a sequence of trials subjects had to guess whether a cross would appear on the left or the right side of a computer screen. The sequence of cross positions was random. Normal controls, manic-depressive patients and patients with senile dementia produced relatively random sequences of responses, as did acute schizophrenic patients with positive symptoms. Acute schizophrenic patients with negative symptoms and chronic patients produced more stereotyped sequences with many response alternations (LRLR). Chronic schizophrenic patients with negative symptoms and intellectual deterioration (defect state) produced very stereotyped sequences with many preservations (LLLL). This severe restriction of response sequences is similar to that shown by animals after treatment with amphetamine. It is suggested that it is due to an impairment of a higher order control process which normally inhibits the repetition of sequences of behaviour when these have proved inappropriate.

Twenty-three acute psychotic patients who were drug free at the time of testing performed a motor task designed to elicit many errors. Normal subjects and many of the psychotic patients were able to correct these errors in the absence of visual feedback. The ability to make such corrections depends on the subject knowing what response he has just made. Patients with experiences of alien control of their thoughts and actions who formed a subgroup of those classified as schizophrenic, were significantly less likely to make error corrections in the absence of visual feedback. This result is consistent with our previous suggestion (Frith, 1987) that these symptoms are a consequence of problems with the central monitoring of responses.

The visual field advantage for letter matching was investigated longitudinally from 5 to 7 yr. A right visual advantage was found with very little indication of any increase with age. Cross-sectional controls exhibited somewhat less of a right visual field advantage. In a group of 4-yr-olds who could not name letters a left visual field advantage was observed for boys. It is suggested that the right visual field advantage for visual-verbal material occurs from a mapping on to an already existing left hemisphere language system.