Judith Allardyce

Incidence of schizophrenia in ethnic minorities in London: ecological study into interactions with environment

Abstract Objective: To determine whether the incidence of schizophrenia among people from non-white ethnic minorities is greater in neighbourhoods where they constitute a smaller proportion of the total population. Design: Ecological design including retrospective study of case records to calculate the incidence of schizophrenia in the ethnic minority population across electoral wards and multi-level analysis to examine interaction between individuals and environment. Setting: 15 electoral wards in Camberwell, South London. Participants: All people aged 16 years and over who had contact with psychiatric services during 1988-97. Main outcome measure: Incidence rates of schizophrenia according to Research Diagnostic Criteria. Results: The incidence of schizophrenia in non-white ethnic minorities increased significantly as the proportion of such minorities in the local population fell. The incidence rate ratio varied in a dose-response fashion from 2.38 (95% confidence interval 1.49 to 3.79) in the third of wards where non-white ethnic minorities formed the largest proportion (28-57%) of the local population to 4.4 (2.49 to 7.75) in the third of wards where they formed the smallest proportion (8-22%). Conclusion: The incidence of schizophrenia in non-white ethnic minorities in London is greater when they comprise a smaller proportion of the local population. What is already known on this topic An increased incidence of schizophrenia has been reported in several ethnic minorities in the United Kingdom Biological risk factors do not seem to explain this Reports from the United States have shown an association between the proportion of an ethnic minority living in an area and their admission rates for mental illness in general What this study adds The lower the proportion of non-white ethnic minorities in a local area the higher the incidence of schizophrenia in those minorities

Reassessing the Long-term Risk of Suicide After a First Episode of Psychosis

CONTEXT The long-term risk of suicide after a first episode of psychosis is unknown because previous studies often have been based on prevalence cohorts, been biased to more severely ill hospitalized patients, extrapolated from a short follow-up time, and have made a distinction between schizophrenia and other psychoses. OBJECTIVE To determine the epidemiology of suicide in a clinically representative cohort of patients experiencing their first episode of psychosis. DESIGN Retrospective inception cohort. SETTING Geographic catchment areas in London, England (between January 1, 1965, and December 31, 2004; n = 2056); Nottingham, England (between September 1, 1997, and August 31, 1999; n = 203); and Dumfries and Galloway, Scotland (between January 1, 1979, and December 31, 1998; n = 464). PARTICIPANTS All 2723 patients who presented for the first time to secondary care services with psychosis in the 3 defined catchment areas were traced after a mean follow-up period of 11.5 years. MAIN OUTCOME MEASURE Deaths by suicide and open verdicts according to the International Classification of Diseases (seventh through tenth editions). RESULTS The case fatality from suicide was considerably lower than expected from previous studies (1.9% [53/2723]); the proportionate mortality was 11.9% (53/444). Although the rate of suicide was highest in the first year after presentation, risk persisted late into follow-up, with a median time to suicide of 5.6 years. Suicide occurred approximately 12 times more than expected from the general population of England and Wales (standardized mortality ratio, 11.65; 95% confidence interval, 8.73-15.24), and 49 of the 53 suicides were excess deaths. Even a decade after first presentation-a time when there may be less intense clinical monitoring of risk-suicide risk remained almost 4 times higher than in the general population (standardized mortality ratio, 3.92; 95% confidence interval, 2.22-6.89). CONCLUSIONS The highest risk of suicide after a psychotic episode occurs soon after presentation, yet physicians should still be vigilant in assessing risk a decade or longer after first contact. The widely held view that 10% to 15% die of suicide is misleading because it refers to proportionate mortality, not lifetime risk. Nevertheless, there is a substantial increase in risk of suicide compared with the general population.

Systematic review and collaborative recalculation of 133,693 incident cases of schizophrenia

BACKGROUND This systematic review and collaborative recalculation was set up to recalculate schizophrenia incidence rates from previously published studies by age and sex. METHOD PubMed, EMBASE and PsycINFO databases were searched (January 1950 to December 2009) for schizophrenia incidence studies. Numerator and population data were extracted by age, sex and, if possible, study period. Original data were requested from the authors to calculate age- and sex-specific incidence rates. Incidence rate ratios (IRRs) with their 95% confidence intervals (CIs) were computed by age and sex from negative binomial regression models. RESULTS Forty-three independent samples met inclusion criteria, yielding 133 693 incident cases of schizophrenia for analysis. Men had a 1.15-fold (95% CI 1.00-1.31) greater risk of schizophrenia than women. In men, incidence peaked at age 20-29 years (median rate 4.15/10,000 person-years, IRR 2.61, 95% CI 1.74-3.92). In women, incidence peaked at age 20-29 (median rate 1.71/10,000 person-years, IRR 2.34, 95% CI 1.66-3.28) and 30-39 years (median rate 1.24/10,000 person-years, IRR 2.25, 95% CI 1.55-3.28). This peak was followed by an age-incidence decline up to age 60 years that was stronger in men than in women (χ² = 57.90, p < 0.001). The relative risk of schizophrenia was greater in men up to age 39 years and this reversed to a greater relative risk in women over the age groups 50-70 years. No evidence for a second incidence peak in middle-aged women was found. CONCLUSIONS Robust sex differences exist in the distribution of schizophrenia risk across the age span, suggesting differential susceptibility to schizophrenia for men and women at different stages of life.

Do symptom dimensions or categorical diagnoses best discriminate between known risk factors for psychosis

ObjectiveTo describe symptom dimensions of psychosis using detailed psychopathological information from epidemiologically defined incident cases which include the full spectrum of functional psychosis across all age ranges. Then, assess the comparative usefulness of the dimensional and categorical representations of psychosis in discriminating between demographic and pre-morbid risk factors.MethodA total of 464 incident cases of psychosis assessed with OPCRIT (Operational Checklist for Psychotic Symptoms) were included in an exploratory factor analysis. Using Regression analyses we modelled the associations of the dimensional and categorical representations of psychosis with antecedent validating variables and compared the subsequent models using the likelihood ratio test.ResultsFactor analysis produced five-symptom dimensions, manic, disorganisation, depressive, delusional and auditory hallucinatory symptoms, explaining 58% of the total variance. Different dimensions were differentially associated with the pre-morbid risk factors. Neither the dimensional nor the categorical representations on their own were sufficient to explain associations with the antecedent validating variables.ConclusionNeither the dimensional or the diagnostic representation of psychosis was superior in discriminating between known risk factors, combining dimensional measures with categorical diagnoses will probably be more informative in determining the causes and correlates of psychosis.

Early risk factors for suicide in an epidemiological first episode psychosis cohort

BACKGROUND Much remains unknown about whether there are early risk factors for suicide in psychosis. AIM The aim of the study was to determine whether there are any identifiable early symptom clusters, aetiological factors or illness course markers for suicide in first episode psychosis. METHOD A total of 2132 patients with first episode psychosis presenting to secondary care services in London (1965-2004; n=1474), Nottingham (1997-1999; n=195) and Dumfries and Galloway (1979-1998; n=463) were traced after up to 40 years (mean 13 years) following first presentation. Risk factors were identified from the Operational Checklist for Psychotic Disorders rated for the first year following presentation. RESULTS Overall, there were 51 suicides and 373 deaths from other causes. Male gender (RR 2.84, 95% CI 1.20-6.69, p=0.02) and a cumulative threshold effect of symptoms early in the illness (RR 6.81, 95% CI 2.33-19.85, p<0.001) were associated with a higher propensity for later completed suicide. There was also a suggestion that early manic symptoms might increase the risk of later suicide irrespective of initial diagnosis. CONCLUSION Suicide risk was associated with a cumulative threshold effect of symptoms and manic symptoms. As suicide is a relatively rare event in psychotic disorders, general population-based prevention strategies may have more impact in this vulnerable group as well as the wider population.

Affectively Salient Meaning in Random Noise: A Task Sensitive to Psychosis Liability

Stable differences in the tendency to attribute meaning and emotional value to experience may represent an indicator of liability to psychosis. A brief task was developed assessing variation in detecting affectively meaningful speech (speech illusion) in neutral random signals (white noise) and the degree to which this was associated with psychometric and familial vulnerability for psychosis. Thirty patients, 28 of their siblings, and 307 controls participated. The rate of speech illusion was compared between cases and controls. In controls, the association between speech illusion and interview-based positive schizotypy was assessed. The hypothesis of a dose-response increase in rate of speech illusion across increasing levels of familial vulnerability for psychosis (controls, siblings of patients, and patients) was examined. Patients were more likely to display speech illusions than controls (odds ratio [OR] = 4.0, 95% confidence interval [CI] = 1.4-11.7), also after controlling for neurocognitive variables (OR = 3.8, 95% CI = 1.04-14.1). The case-control difference was more accentuated for speech illusion perceived as affectively salient (positively or negatively appraised) than for neutrally appraised speech illusions. Speech illusion in the controls was strongly associated with positive schizotypy but not with negative schizotypy. In addition, the rate of speech illusion increased with increasing level of familial risk for psychotic disorder. The data suggest that the white noise task may be sensitive to psychometric and familial vulnerability for psychosis associated with alterations in top-down processing and/or salience attribution.

Seeking Verisimilitude in a Class: A Systematic Review of Evidence That the Criterial Clinical Symptoms of Schizophrenia Are Taxonic

This review examines whether there is evidence that the criterion symptoms of Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) (DSM-IV) schizophrenia are taxonic--that schizophrenia is not part of a single distribution of normality. Two taxometric methods, coherent cut kinetics (CCK) and latent variable modeling (LVM), are demonstrated to be sensitive to latent classes and, therefore, were regarded as providing relevant statistical evidence. A systematic literature search identified 24 articles describing analyses of 28 participant cohorts in which CCK or LVM methods were used with one or more criterion symptoms of schizophrenia. Virtually all analyses yielded results that, on first impression, favored taxonic over dimensional interpretations of the latent structure of schizophrenia. However, threats to the internal and external validity of these studies--including biased or inadequate analyses, violation of statistical assumptions, inadequate indicator screening, and the introduction of systematic error through recruitment and sampling--critically undermine this body of work. Uncertainties about the potential effects of perceptual biases, unimodal assessment, and item parceling are also identified, as are limitations in seeking to validate classes with single or double dissociations of outcomes. We conclude that there is no reason to seriously doubt a single-distribution model of schizophrenia because there is no evidence that provides a serious test of this null hypothesis. A second fundamental question remains outstanding: is schizophrenia truly a group of schizophrenias, with taxonic divisions separating its types? We make design and analysis suggestions for future research addressing these questions.

Mortality in first-contact psychosis patients in the UK: a cohort study

BACKGROUND The excess mortality following first-contact psychosis is well recognized. However, the causes of death in a complete incidence cohort and mortality patterns over time compared with the general population are unknown. METHOD All 2723 patients who presented for the first time with psychosis in three defined catchment areas of the U.K. in London (1965-2004, n=2056), Nottingham (1997-1999, n=203) and Dumfries and Galloway (1979-1998, n=464) were traced after a mean of 11.5 years follow-up and death certificates were obtained. Data analysis was by indirect standardization. RESULTS The overall standardized mortality ratio (SMR) for first-contact psychosis was 184 [95% confidence interval (CI) 167-202]. Most deaths (84.2%, 374/444) were from natural causes, although suicide had the highest SMR (1165, 95% CI 873-1524). Diseases of the respiratory system and infectious diseases had the highest SMR of the natural causes of death (232, 95% CI 183-291). The risk of death from diseases of the circulatory system was also elevated compared with the general population (SMR 139, 95% CI 117-164) whereas there was no such difference for neoplasms (SMR 111, 95% CI 86-141). There was strong evidence that the mortality gap compared with the general population for all causes of death (p<0.001) and all natural causes (p=0.01) increased over the four decades of the study. There was weak evidence that cardiovascular deaths may be increasing relative to the general population (p=0.07). CONCLUSIONS People with first-contact psychosis have an overall mortality risk that is nearly double that of the general population. Most excess deaths are from natural causes. The widening of the mortality gap over the last four decades should be of concern to all clinicians involved in delivering healthcare.

Kraepelin Was Right: A Latent Class Analysis of Symptom Dimensions in Patients and Controls

Phenotypic heterogeneity within patients and controls may explain why the genetic variants contributing to schizophrenia risk explain only a fraction of the heritability. The aim of this study is to investigate quantitative and qualitative differences in psychosis symptoms in a sample including psychosis patients, their relatives, and community controls. We combined factor analysis and latent class analysis to analyze variation in Comprehensive Assessment of Symptoms and History lifetime-rated symptoms in 4286 subjects. The Wechsler Adult Intelligence Scale-Intelligence Quotient (N = 2663) and the Camberwell Assessment of Need rating scale (N = 625) were assessed in a subsample. Variation in 5 continuous dimensions (disorganization, positive, negative, mania, and depression) was accounted for by the presence of 7 homogeneous classes (Kraepelinian schizophrenia, affective psychosis, manic-depression, deficit nonpsychosis, depression, healthy, and no symptoms). Eighty-five percent of the schizophrenia patients was assigned to the Kraepelinian schizophrenia class (characterized by high scores on the 5 dimensions, low IQ, and poor outcome) while 15% was assigned to the affective psychosis class (relatively low disorganization and negative scores, normal IQ, and good outcome). In bipolar patients (91% bipolar I), 41% was assigned to the Kraepelinian schizophrenia class, 44% to the affective psychosis class, and 10% to the manic-depression class. Latent class membership was associated with intelligence in psychosis patients and in their relatives but not in community controls. In conclusion, symptom heterogeneity is more pronounced in bipolar disorder compared with schizophrenia. Reducing phenotypic heterogeneity within psychosis patients and controls may facilitate etiological research.

Nithsdale Schizophrenia Surveys 21: a longitudinal study of National Adult Reading Test stability

Background. The stability of the National Adult Reading Test (NART) as a measure of pre-morbid intelligence in schizophrenia has not yet been satisfactorily established despite the widespread use of the NART in schizophrenia research. Method. We examined NART stability in a diverse group of 45 schizophrenic patients in a prospective longitudinal study over 6·5–7·5 years. Results. The results showed that NART performance does not decline significantly with increasing duration of schizophrenic illness and that test–retest reliability, even over 6·5–7·5 years, is extremely high. Discussion. Our results provide the necessary evidence that the NART can be used as a stable measure of pre-morbid intelligence in schizophrenia.