Jane Boydell

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

Incidence of Schizophrenia and Other Psychoses in England, 1950–2009: A Systematic Review and Meta-Analyses

Background We conducted a systematic review of incidence rates in England over a sixty-year period to determine the extent to which rates varied along accepted (age, sex) and less-accepted epidemiological gradients (ethnicity, migration and place of birth and upbringing, time). Objectives To determine variation in incidence of several psychotic disorders as above. Data Sources Published and grey literature searches (MEDLINE, PSycINFO, EMBASE, CINAHL, ASSIA, HMIC), and identification of unpublished data through bibliographic searches and author communication. Study Eligibility Criteria Published 1950–2009; conducted wholly or partially in England; original data on incidence of non-organic adult-onset psychosis or one or more factor(s) pertaining to incidence. Participants People, 16–64 years, with first -onset psychosis, including non-affective psychoses, schizophrenia, bipolar disorder, psychotic depression and substance-induced psychosis. Study Appraisal and Synthesis Methods Title, abstract and full-text review by two independent raters to identify suitable citations. Data were extracted to a standardized extraction form. Descriptive appraisals of variation in rates, including tables and forest plots, and where suitable, random-effects meta-analyses and meta-regressions to test specific hypotheses; rate heterogeneity was assessed by the I2-statistic. Results 83 citations met inclusion. Pooled incidence of all psychoses (N = 9) was 31.7 per 100,000 person-years (95%CI: 24.6–40.9), 23.2 (95%CI: 18.3–29.5) for non-affective psychoses (N = 8), 15.2 (95%CI: 11.9–19.5) for schizophrenia (N = 15) and 12.4 (95%CI: 9.0–17.1) for affective psychoses (N = 7). This masked rate heterogeneity (I2: 0.54–0.97), possibly explained by socio-environmental factors; our review confirmed (via meta-regression) the typical age-sex interaction in psychosis risk, including secondary peak onset in women after 45 years. Rates of most disorders were elevated in several ethnic minority groups compared with the white (British) population. For example, for schizophrenia: black Caribbean (pooled RR: 5.6; 95%CI: 3.4–9.2; N = 5), black African (pooled RR: 4.7; 95%CI: 3.3–6.8; N = 5) and South Asian groups in England (pooled RR: 2.4; 95%CI: 1.3–4.5; N = 3). We found no evidence to support an overall change in the incidence of psychotic disorder over time, though diagnostic shifts (away from schizophrenia) were reported. Limitations Incidence studies were predominantly cross-sectional, limiting causal inference. Heterogeneity, while evidencing important variation, suggested pooled estimates require interpretation alongside our descriptive systematic results. Conclusions and Implications of Key Findings Incidence of psychotic disorders varied markedly by age, sex, place and migration status/ethnicity. Stable incidence over time, together with a robust socio-environmental epidemiology, provides a platform for developing prediction models for health service planning.

Pathways to schizophrenia: the impact of environmental factors

Schizophrenia is an aetiologically complex disorder arising from the interaction of a range of factors acting at various stages of life. Schizophrenic individuals inherit genes that cause structural brain deviations which may be compounded by early environmental insults. As a result some pre-schizophrenic children exhibit subtle developmental delays, cognitive problems, or poor interpersonal relationships. They are susceptible to dysregulation of dopamine, the final pathway leading to the onset of a psychotic illness. Dopamine dysregulation may arise through a process of sensitization, which, in animals, can be caused by repeated administration of dopamine-releasing drugs. It is clear that the same process occurs in humans, and that some individuals are particularly sensitive to the effects of such drugs for either genetic reasons or through early environmental damage. Stress has also been shown to induce dopamine release in animal studies, and epidemiological studies have demonstrated that social stresses can precipitate schizophrenia. Thus, stresses, such as drug use and social adversity, in adolescence or early adult life may propel the neurodevelopmentally impaired individual over a threshold into frank psychosis.

Cumulative social disadvantage, ethnicity and first-episode psychosis: a case-control study

BACKGROUND Numerous studies have reported high rates of psychosis in the Black Caribbean population in the UK. Recent speculation about the reasons for these high rates has focused on social factors. However, there have been few empirical studies. We sought to compare the prevalence of specific indicators of social disadvantage and isolation, and variations by ethnicity, in subjects with a first episode of psychosis and a series of healthy controls. METHOD All cases with a first episode of psychosis who made contact with psychiatric services in defined catchment areas in London and Nottingham, UK and a series of community controls were recruited over a 3-year period. Data relating to clinical and social variables were collected from cases and controls. RESULTS On all indicators, cases were more socially disadvantaged and isolated than controls, after controlling for potential confounders. These associations held when the sample was restricted to those with an affective diagnosis and to those with a short prodrome and short duration of untreated psychosis. There was a clear linear relationship between concentrated disadvantage and odds of psychosis. Similar patterns were evident in the two main ethnic groups, White British and Black Caribbean. However, indicators of social disadvantage and isolation were more common in Black Caribbean subjects than White British subjects. CONCLUSIONS We found strong associations between indicators of disadvantage and psychosis. If these variables index exposure to factors that increase risk of psychosis, their greater prevalence in the Black Caribbean population may contribute to the reported high rates of psychosis in this population.

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.

Ethnicity, social disadvantage and psychotic-like experiences in a healthy population based sample

Objective: We sought to investigate the prevalence and social correlates of psychotic‐like experiences in a general population sample of Black and White British subjects.

Testing the association between the incidence of schizophrenia and social capital in an urban area

BACKGROUND Social capital has been considered aetiologically important in schizophrenia but the empirical evidence to support this hypothesis is absent. We tested whether social capital, measured at the neighbourhood level, was associated with the incidence of schizophrenia (ICD-10 F20). MethodWe administered a cross-sectional questionnaire on social capital to 5% of the adult population in 33 neighbourhoods (wards) in South London (n=16 459). The questionnaire contained items relating to two social capital constructs: social cohesion and trust (SC&T) and social disorganization (SocD). Schizophrenia incidence rates, estimated using data from the Aetiology and Ethnicity in Schizophrenia and Other Psychoses (AESOP) study, provided the outcome. We used multi-level Poisson regression to test our hypothesis while controlling for individual- and neighbourhood-level characteristics. RESULTS We identified 148 cases during 565 576 person-years at-risk. Twenty-six per cent of the variation in incidence rates was attributable to neighbourhood-level characteristics. Response from the social capital survey was 25.7%. The association between SC&T and schizophrenia was U-shaped. Compared with neighbourhoods with medial levels of SC&T, incidence rates were significantly higher in neighbourhoods with low [incidence rates ratio (IRR) 2.0, 95% confidence interval (CI) 1.2-3.3] and high (IRR 2.5, 95% CI 1.3-4.8) levels of SC&T, independent of age, sex, ethnicity, ethnic density, ethnic fragmentation and socio-economic deprivation. ConclusionNeighbourhood variation in SC&T was non-linearly associated with the incidence of schizophrenia within an urban area. Neighbourhoods with low SC&T may fail to mediate social stress whereas high SC&T neighbourhoods may have greater informal social control or may increase the risk of schizophrenia for residents excluded from accessing available social capital.

Suicide and other causes of mortality in bipolar disorder: a longitudinal study

BACKGROUND The high risk of suicide in bipolar disorder is well recognized, but may have been overestimated. There is conflicting evidence about deaths from other causes and little known about risk factors for suicide. We aimed to estimate suicide and mortality rates in a cohort of bipolar patients and to identify risk factors for suicide. METHOD All patients who presented for the first time with a DSM-IV diagnosis of bipolar I disorder in a defined area of southeast London over a 35-year period (1965-1999) were identified. Mortality rates were compared with those of the 1991 England and Wales population, indirectly standardized for age and gender. Univariate and multivariate analyses were used to test potential risk factors for suicide. RESULTS Of the 239 patients in the cohort, 235 (98.3%) were traced. Forty-two died during the 4422 person-years of follow-up, eight from suicide. The standardized mortality ratio (SMR) for suicide was 9.77 [95% confidence interval (CI) 4.22-19.24], which, although significantly elevated compared to the general population, represented a lower case fatality than expected from previous literature. Deaths from all other causes were not excessive for the age groups studied in this cohort. Alcohol abuse [hazard ratio (HR) 6.81, 95% CI 1.69-27.36, p=0.007] and deterioration from pre-morbid level of functioning up to a year after onset (HR 5.20, 95% CI 1.24-21.89, p=0.024) were associated with increased risk of suicide. CONCLUSIONS Suicide is significantly increased in unselected bipolar patients but actual case fatality is not as high as previously claimed. A history of alcohol abuse and deterioration in function predict suicide in bipolar disorder.

The association of inequality with the incidence of schizophrenia - an ecological study

AbstractBackgroundSocio–economic factors are known to be associated with schizophrenia, but no studies have investigated the effect of inequality on incidence rates of schizophrenia. The aim of the study was to determine whether those electoral wards with greater inequality have a higher incidence of schizophrenia.MethodAn ecological study was carried out involving a retrospective case record study to calculate the incidence of schizophrenia across wards in Camberwell, South London for the period 1988–1997, and an index of inequality within each ward was calculated.ResultsThere was no significant effect of inequality overall. However, in the group of deprived wards, the incidence of RDC schizophrenia increased as inequality increased (IRR 3.79, 95 %CI 1.25.11.49 p = 0.019 after adjusting for age, sex, absolute deprivation, ethnicity, proportion of ethnic minorities and the interaction between individual ethnicity and proportion of ethnic minorities.ConclusionIncreased inequality is associated with increasing incidence of schizophrenia, but only in the most deprived areas. This is independent of other known social risk factors.

Incidence and distribution of first-episode mania by age: results from a 35-year study

BACKGROUND Few epidemiological studies have investigated incidence by age or age at onset distributions for mania or bipolar disorder. The current study aimed to determine these in a defined area in south-east London, over a 35-year period. METHOD All cases of first-episode mania presenting to psychiatric services in Camberwell, south-east London, between 1965 and 1999 were identified. Incidence rates by age, using 5-year age-at-onset bands, were estimated and the structure of the age-at-onset distribution for first-episode mania was investigated using finite mixture distributions (admixture analysis). RESULTS The incidence of DSM-IV bipolar I disorder (BP I), first manic episode peaked in early adult life (16.38/100,000 population per year in the 21-25 years band) with a much smaller peak in mid-life. A two-component normal mixture distribution fitted age at onset better than either a single normal distribution or a three-component mixture, implying the existence of early and later onset subgroups. The early onset group had a stronger family history of bipolar disorder, and showed more acute, severe and atypical symptoms during their first manic episode. CONCLUSIONS The incidence of mania peaks in early adult life but there is clear evidence of early and later onset subgroups which may represent different forms of disorder.