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Biomedical subjects

S W Lewis

Publications and source records attributed to S W Lewis.

At least 37 records · Page 2Linked to original sources
PubMed1996

Do obstetric complications cause the earlier age at onset in male than female schizophrenics?

We compared the age at onset of 184 patients with functional psychoses with and without a history of obstetric complications (OCs) as defined by the scale of Lewis et al. (1989). OCs had no significant influence on the age at onset in those patients who had affective psychoses or were non-white. There were 73 white patients with a DSM-III-R diagnosis of schizophrenia. The mean age at onset of those 25 who had a history of at least one definite OC was 2.6 years earlier than that of the 48 patients with no history of OCs. This effect was entirely due to the male patients with histories of OCs who had, on average, a 3.5 years earlier age at onset. There were no gender differences in age at onset among schizophrenics without a history of OCs. We suggest that a subgroup of male patients with a history of OCs is responsible for the earlier age at onset in male compared to female schizophrenics.

Black or African American↗
PubMed1996

Abnormal saccadic distractibility in patients with schizophrenia: a 99mTc-HMPAO SPET study.

Recent research has shown that some patients with schizophrenia have a severe impairment in the suppression of reflexive saccadic eye movements in the ANTI-saccade task. This saccadic distractibility has previously been found in patients with lesions of dorsolateral prefrontal cortex, implicating an abnormality of prefrontal cortex. The objective of the present study was to determine the contribution of these and other areas to the ANTI-saccadic abnormality in schizophrenia by functional neuroimaging. Using 99mtechnetium-HMPAO high resolution multidetector single-photon emission tomography, regional cerebral blood flow (rCBF) during performance of the ANTI-saccade eye-movement task was compared, by statistical parametric mapping, in ten male schizophrenic patients on stable antipsychotic medication who had a high distractibility error rate on the task, and eight similar patients who had normal distractibility error rates. Compared with the normal error group, the patients with high error rates showed significantly decreased rCBF bilaterally, in the anterior cingulate, insula, and in left striatum. These same patients also had increased perseverative errors on the Wisconsin Card Sort Test.

Adult↗
PubMed1996

Bipolar affective disorder minus left prefrontal cortex equals schizophrenia.

BACKGROUND: An investigation of the relationship between bipolar affective disorder and schizophrenia, following a severe head injury and removal of the left prefrontal cortex. METHOD: A single case report. RESULTS: An individual with past history of bipolar affective disorder suffered traumatic damages to the left prefrontal cortex with a second lesion in the left temporal lobe. The patient developed typical schizophrenia nine months later. The relevance of his brain lesions in determining the schizophrenic symptoms is discussed. CONCLUSION: We propose that the specific pattern of brain injury in this patient was sufficient to change the phenotype from bipolar affective disorder to schizophrenia.

Adult↗
PubMed1996

An investigation of motor function in schizophrenia using transcranial magnetic stimulation of the motor cortex.

BACKGROUND: In this first investigation of motor function in schizophrenia using transcranial magnetic stimulation (TMS), the general hypothesis tested was that this methodology could be used to investigate the disruption of corticospinal inhibitory processes suggested by cognitive and psychophysiological paradigms. METHOD: Nine drug-free DSM-IV schizophrenic patients were compared with nine age- and sex-matched normal subjects. Electromyographic (EMG) recordings were made from the thenar muscles of the dominant hand during sustained, weak voluntary contraction. TMS over a particular threshold applied to the motor cortex would elicit a compound motor evoked potential (cMEP) followed by a period of suppression of EMG. RESULTS: The latency of cMEPs following TMS was significantly shorter in the schizophrenic patients. The two groups did not differ significantly with respect to mean latency of suppression of EMG activity, or stimulus thresholds for either cMEPs or EMG suppression. CONCLUSION: These findings could be the result of a relative lack of corticospinal inhibition of motor responses; a change in the site of TMS activation; or an abnormality of peripheral nervous function in schizophrenia. Drug effects were unlikely since seven of the patients were drug-naive.

Adult↗
PubMed1994

Admission of British Caribbeans to mental hospitals: is it a cohort effect?

Work in the 1980s has shown that the high incidence of schizophrenia in British Caribbean men is restricted to those born after 1950. Data from a study of admissions in three London health districts suggested that the greater part of this excess risk may be confined to those born before 1966. This suggests that the group of British Caribbean men experiencing a high frequency of schizophrenia could be a tightly delineated birth cohort. If confirmed in wider studies, this could have important implications for the elucidation of the causes of one type of schizophrenia.

Adolescent↗
PubMed1994

Cerebral ventricle dimensions as risk factors for schizophrenia and affective psychosis: an epidemiological approach to analysis.

A case-control study was undertaken of volumetric computerized tomographic scan measures in 216 consecutive admissions for functional psychosis and 67 healthy community controls. Odds ratio analysis demonstrated significant linear trends in the association between increasing lateral and third ventricle volumes, and both RDC schizophrenia (N = 121) and schizo-affective disorder (N = 41); cases were consistently associated with larger volumes than controls. There was an association between larger third, but not lateral, ventricle size in affective psychoses (N = 54). These associations were statistically independent of intracranial volume, sex, social class and ethnicity, factors which were significantly associated with ventricular measures in the controls. There was no evidence of a threshold corresponding to the notion of normal versus enlarged ventricles. Within the schizophrenia group, there were no large or significant associations between ventricle dimensions and age at onset, duration of illness or pre-morbid social functioning. Neither obstetric complications nor a family history of schizophrenia or other psychiatric illness was associated with large ventricles in these cases.

Adolescent↗
PubMed1994

Prevalence of delusional misidentification syndromes.

The prevalence of delusional misidentification syndromes (DMS) in a consecutive sample of 195 inpatient admissions with functional psychosis was found to be 4.1%. It is argued that DMS symptoms are more common than previously supposed.

Adult↗
PubMed1994

Cerebral hemiatrophy and schizophrenia.

BACKGROUND: Neuroimaging of a treatment-resistant patient with schizophrenia revealed the existence of cerebral hemiatrophy. The association of schizophrenia with cerebral hemiatrophy has not previously been reported. RESULTS: Neuroimaging with X-ray computerised tomography showed marked reduction in the volume of the left cerebral hemisphere with secondary enlargement of the left lateral fissure and cortical sulci. High resolution cranial single-photon emission computerised tomography showed a functional deficit of the regional cerebral blood flow in the left lateral parietal and left temporal lobes. CONCLUSIONS: Cerebral hemiatrophy may belong to the lengthening list of neurodevelopmental cerebral anomalies associated with schizophrenia.

Adult↗
PubMed1994

Inner london collaborative audit of admissions in two health districts. I: Introduction, methods and preliminary findings.

BACKGROUND: There is pressure on acute admission services in inner-city areas. Two deprived London districts with markedly different acute bed ratios but similar sociodemographic backgrounds were compared to test the hypothesis that more facilities mean better service. METHOD: An instrument for auditing the use of short-stay hospital beds was constructed to collect information concerning admissions to, and short-stay patients in, the chosen districts during a three-month period. RESULTS: There was a higher admission rate and substantially greater use of beds per unit population in south Southwark than in Hammersmith & Fulham. Much of the difference was attributable to a higher rate of admission of patients with affective disorders in south Southwark. CONCLUSIONS: The results are not explained by variations in population need, longer in-patient stay, or poorer aftercare leading to early relapse. The question of whether there is over-provision of services compared with real need in south Southwark, or under-provision (particularly for people with affective disorders) in Hammersmith & Fulham, is considered but left open for discussion following a study of ethnic issues and the reasons for admission.

Adult↗
PubMed1994

Inner London collaborative audit of admissions in two health districts. II: Ethnicity and the use of the Mental Health Act.

BACKGROUND: Twenty-six per cent of patients in two Inner London districts were admitted to acute wards under the provisions of the Mental Health Act. Compared with those not under compulsion, they were young, male, more likely to be of black Caribbean origin, and to have a diagnosis of schizophrenia of short duration. The hypothesis is tested that ethnicity determines rates of compulsory admission independently of the other factors. METHOD: Sampling and data collection methods were described in the first paper. Statistical analyses included a log-linear analysis of six key variables: compulsory admission, challenging behaviour, diagnosis, ethnicity, age, and sex. RESULTS: There were no substantial differences between districts. Analysis provided two similar statistical models. In both, admission under the Act was strongly associated with challenging behaviour and diagnosis of schizophrenia. In the model of best fit there was no significant interaction term for ethnicity and compulsion. In the second model there was a weak association. CONCLUSIONS: Ethnicity did not appear to be of outstanding importance in decisions to use the Mental Health Act. There was a strong link between ethnicity and diagnosis, independent of compulsion. Differences between the districts made no major contribution to the rates of compulsory admission.

Age Factors↗
PubMed1994

Inner london collaborative audit of admission in two health districts. III: Reasons for acute admission to psychiatric wards.

BACKGROUND: In this series, rates of admission and daily bed use in south Southwark were 30% higher than in Hammersmith & Fulham, principally because of a higher rate of admission for affective disorders. Factors associated with compulsory admission did not differ between the districts. This final paper examines the severity of symptoms, the reasons given for admission and factors relevant to the judgement to admit, in order to test the hypothesis that more resources mean better service. METHOD: Sampling and data collection methods were described in the first paper. RESULTS: In both districts, major reasons for admission were self-neglect and risk of self-harm, poor adaptive functioning, and poor acceptance of medication. In south Southwark, a group of patients had affective disorders and less severe symptoms but a stated risk of suicide. Rates for, and severity of, schizophrenia were similar in the two districts. Social and preventive reasons for admission were given more frequently in south Southwark, where patients had more often been in contact with services before admission. Staff there, but not in Hammersmith & Fulham, suggested that many could have benefited from alternative forms of residential care. CONCLUSIONS: A 'buffer' of hospital beds in south Southwark may have allowed a more acceptable service, particularly for affective disorders. The possibility that this buffer could be replaced by a wider range of residential accommodation, including hostels away from the District General Hospital, is discussed. Ten recommendations are listed.

Adult↗
PubMed1993

Reduction of cortical volume in schizophrenia on magnetic resonance imaging.

The MRI scans of 48 schizophrenic patients, fulfilling RDC criteria, were compared to those of 34 healthy controls matched for age, ethnicity and parental social class. The volume of the frontal and anterior parietal lobes was significantly reduced in the schizophrenic group as a result of a selective decrease in cortical volume, with a corresponding increase in the volume of sulcal fluid. Reduction in the volume of the temporal grey matter was more marked on the right, but was not in excess of the loss of volume observed in other areas of the cortex. MRI abnormalities correlated poorly with clinical parameters, although both unemployment and poor pre-morbid adjustment predicted reduced cerebral volume and increased sulcal volume. These results question whether the medial temporal lobes are the only site of structural pathology in schizophrenia.

Adult↗
PubMed1993

A case-control study of family history and cerebral cortical abnormalities in schizophrenia.

The relationship between family history of psychosis and cortical sulcal widening on CT scans was investigated. Forty-two schizophrenic subjects with a positive family history were individually matched to 42 schizophrenics with no documented family history and 42 healthy controls. Abnormally wide sulci, as defined on the basis of the normal control data, were significantly more common in the family history negative group (9/42) than in the family history positive group (1/42) or the controls (2/36). No significant correlation was found between cerebral cortical ratings and ventricular size.

Case-Control Studies↗
PubMed1993

Premorbid social underachievement in schizophrenia. Results from the Camberwell Collaborative Psychosis Study.

In an investigation of the timing and precursors of social decline in schizophrenia and affective psychosis, 195 subjects from the Camberwell Collaborative Psychosis Study were currently of lower social class than were their fathers. A comparison between father's occupation and proband's best premorbid occupational level indicated underachievement confined to DSM-III schizophrenia, there being no such effect in affective psychosis. Decline in social status following onset of psychosis, analysed by comparing best premorbid occupation with current occupation, was marked in both schizophrenia and affective psychosis, indicating a non-specific effect. Schizophrenic patients who failed to achieve their fathers' social status had poorer educational qualifications than those who equalled or bettered their paternal social class, despite similar premorbid IQ (NART) scores and age at onset of psychosis. These results indicate that schizophrenia may be manifest before the onset of psychosis, and lend weight to the notion of a developmental origin to this disorder.

Adolescent↗
PubMed1993

A twin study of psychosis and criminality.

Lifetime criminal and psychiatric histories were examined in a consecutive series of 280 individuals of twin birth with a diagnosis of major functional psychosis who were seen and followed up at the Maudsley Hospital between 1948 and 1988. Their 210 co-twins, 35% of whom had a similar diagnosis, were ascertained and followed up over the same period. In the absence of reliable general-population estimates for lifetime conviction rates, co-twins were used as case controls. Among the 220 complete pairs, significantly more probands (25.7%) than co-twins (14.0%) were convicted, although there was no evidence for an independent genetic basis for criminal behaviour. Criminal conviction was significantly related to psychiatric diagnosis. There were specific patterns of offending, particularly among the schizophrenic men, who were also significantly more often convicted (48.6%) than the men with affective psychosis (19.4%), and more likely to receive a prison sentence. The schizophrenic patients were younger at their first conviction (mean age 22.6 years v. 30.8 years) and they had committed more violent offences than the affective group. In both diagnostic groups, ages at first psychiatric contact and first conviction were highly correlated.

Adolescent↗
PubMed1992

A controlled study of 99mTc-HMPAO single-photon emission imaging in chronic schizophrenia.

Regional cerebral blood flow (rCBF) during a word fluency task was compared in twenty-five male, right-handed, medicated schizophrenic patients and twenty-five age-matched male, right-handed healthy volunteers, using 99mtechnetium-HMPAO multidetector single-photon emission tomography. Increased rCBF in caudate and thalamus was found in patients, probably secondary to neuroleptic medication. Patients showed decreased rCBF in left frontal cortical regions and increased rCBF in left posterior cortical regions, compared to controls. Patterns of left-sided frontal rCBF dominance in controls were reversed in patients, as were normal patterns of right-sided parietal rCBF dominance. Negative symptom score correlated inversely with mesial frontal rCBF, particularly on the left.

Adult↗