Change in incidence rates for psychosis in different ethnic groups in south London: findings from the Clinical Record Interactive Search-First Episode Psychosis (CRIS-FEP) study

Abstract

Background A higher incidence of psychotic disorders has been consistently reported among black and other minority ethnic groups, particularly in northern Europe. It is unclear whether these rates have changed over time. Methods We identified all individuals with a first episode psychosis who presented to adult mental health services between 1 May 2010 and 30 April 2012 and who were resident in London boroughs of Lambeth and Southwark. We estimated age-and-gender standardised incidence rates overall and by ethnic group, then compared our findings to those reported in the Aetiology and Ethnicity of Schizophrenia and Other Psychoses (ÆSOP) study that we carried out in the same catchment area around 10 years earlier. Results From 9109 clinical records we identified 558 patients with first episode psychosis. Compared with ÆSOP, the overall incidence rates of psychotic disorder in southeast London have increased from 49.4 (95% confidence interval (CI) 43.6–55.3) to 63.1 (95% CI 57.3–69.0) per 100 000 person-years at risk. However, the overall incidence rate ratios (IRR) were reduced in some ethnic groups: for example, IRR (95% CI) for the black Caribbean group reduced from 6.7 (5.4–8.3) to 2.8 (2.1–3.6) and the ‘mixed’ group from 2.7 (1.8–4.2) to 1.4 (0.9–2.1). In the black African group, there was a negligible difference from 4.1 (3.2–5.3) to 3.5 (2.8–4.5). Conclusions We found that incidence rates of psychosis have increased over time, and the IRR varied by the ethnic group. Future studies are needed to investigate more changes over time and determinants of change.

Temporal trends in psychotic symptoms: Repeated cross-sectional surveys of the population in England 2000–14

“…The lack of a proportionate rise in psychotic symptoms could be due to a large number of people whose symptoms are in remission, perhaps due to effective treatment, or who have only negative symptoms that could not be detected by the PSQ. This would be consistent with the findings from the 2019 study of incidence rates of first episode psychosis (Oduola et al, 2019). However development of Early Intervention (EIS) services could have partially explained the apparent increase rates in this study through greater case identification (Oduola et al, 2019).…”

“…A systematic review of the incidence and prevalence of psychotic disorders in England found no convincing evidence that psychotic illnesses had increased between 1950 and 2009 (Kirkbride et al, 2012). In contrast, an investigation based on UK electronic health records did find an increase in the incidence of diagnosed psychotic illnesses between 1996-1999 and 2010-2012, which varied in different ethnic groups (Oduola et al, 2019).…”

Schizophrenia, catatonic schizophrenia and poliovirus – a role for natural experiments?

“…The findings of this paper are relevant for developing research in psychiatry. Firstly, the finding of reduced overall incidence of schizophrenia is consistent with some previous findings 7 . Given that reduction in incidence of catatonia subtype of schizophrenia is more marked, it is plausible that reduction in incidence of this schizophrenia subtype accounts for the reduction in schizophrenia incidence overall observed in previous research.…”

“…Firstly, the finding of reduced overall incidence of schizophrenia is consistent with some previous findings. 7 Given that reduction in incidence of catatonia subtype of schizophrenia is more marked, it is plausible that reduction in incidence of this schizophrenia subtype accounts for the reduction in schizophrenia incidence overall observed in previous research. Tanskanen et al's paper also contributes further evidence consistent with some causal impact of polio on the occurrence of catatonic schizophrenia.…”

Migration, ethnicity and psychoses: evidence, models and future directions

“…Moreover, incidence rates may change over time. In our most recent study, in which we compared incidence rates in South London between 1997‐1999 and 2010‐2012, we found notable changes in incidence by ethnic group. For example, rates in the White British population increased from 20 per 100,000 in 1997‐1999 to 39 per 100,000 in 2010‐2012.…”