A comparison of neighbourhood level variation and risk factors for affective versus non-affective psychosis

Variation of subclinical psychosis across 16 sites in Europe and Brazil: findings from the multi-national EU-GEI study

BACKGROUND

Incidence of first-episode psychosis (FEP) varies substantially across geographic regions. Phenotypes of subclinical psychosis (SP), such as psychotic-like experiences (PLEs) and schizotypy, present several similarities with psychosis. We aimed to examine whether SP measures varied across different sites and whether this variation was comparable with FEP incidence within the same areas. We further examined contribution of environmental and genetic factors to SP.

METHODS

We used data from 1497 controls recruited in 16 different sites across 6 countries. Factor scores for several psychopathological dimensions of schizotypy and PLEs were obtained using multidimensional item response theory models. Variation of these scores was assessed using multi-level regression analysis to estimate individual and between-sites variance adjusting for age, sex, education, migrant, employment and relational status, childhood adversity, and cannabis use. In the final model we added local FEP incidence as a second-level variable. Association with genetic liability was examined separately.

RESULTS

Schizotypy showed a large between-sites variation with up to 15% of variance attributable to site-level characteristics. Adding local FEP incidence to the model considerably reduced the between-sites unexplained schizotypy variance. PLEs did not show as much variation. Overall, SP was associated with younger age, migrant, unmarried, unemployed and less educated individuals, cannabis use, and childhood adversity. Both phenotypes were associated with genetic liability to schizophrenia.

CONCLUSIONS

Schizotypy showed substantial between-sites variation, being more represented in areas where FEP incidence is higher. This supports the hypothesis that shared contextual factors shape the between-sites variation of psychosis across the spectrum.

Neighborhood social composition and refugee mental health - quasi-experimental evidence of associations from a Danish population register study

BACKGROUND

Refugees are at an elevated risk of some mental disorders with studies highlighting the contributing role of post-migration factors. Studies of migrant groups show neighborhood social composition, such as ethnic density, to be important. This is the first longitudinal study to examine this question for refugees and uses a novel quasi-experimental design.

METHODS

We followed a cohort of 44 033 refugees from being first assigned housing under the Danish dispersal policy, operating from 1986 to 1998, until 2019. This comprised, in effect, a natural experiment whereby the influence of assigned neighborhood could be determined independently of endogenous factors. We examined three aspects of neighborhood social composition: proportion of co-nationals, refugees, and first-generation migrants; and subsequent incidence of different mental disorders.

RESULTS

Refugees assigned to neighborhoods with fewer co-nationals (lowest v. highest quartile) were more likely to receive a subsequent diagnosis of non-affective psychosis, incident rate ratio (IRR) 1.25 (95% confidence interval (CI) 1.06-1.48), and post-traumatic stress disorder (PTSD), IRR 1.21 (95% CI I.05-1.39). A comparable but smaller effect was observed for mood disorders but none observed for stress disorders overall. Neighborhood proportion of refugees was less clearly associated with subsequent mental disorders other than non-affective psychosis, IRR 1.24 (95% CI 1.03-1.50). We found no statistically significant associations with proportion of migrants.

CONCLUSIONS

For refugees, living in a neighborhood with a lower proportion of co-nationals is related to subsequent increased risk of diagnosed mental disorders particularly non-affective psychosis and PTSD.

Urbanization and psychosis: an update of recent evidence

PURPOSE OF REVIEW

Urbanization, a complex global phenomenon, has a significant bearing on schizophrenia/psychosis burden through various socioeconomic and environmental factors. This review focuses on recent evidence (2019-2023) linking urbanization, schizophrenia, and the role of green space.

RECENT FINDINGS

This review analyzed 43 articles that examined the correlation between urban birth or upbringing, urban living (urbanicity), and various schizophrenia/psychosis-related outcomes such as incidence, psychotic experiences, etc. The studies showed differing results across geographical locations. Socioeconomic factors like area deprivation, migrant status (ethnic density) and social fragmentation were independently associated with the risk of schizophrenia/psychosis irrespective of urbanicity. More recently, environmental factors such as green space reduction and air pollution have been explored in urban living conditions and were positively associated with an increased risk of schizophrenia/psychosis.

SUMMARY

There is a need for further investigation in low and middle-income countries. The impact of urbanization-related factors and green space on the risk of schizophrenia/psychosis calls for appropriate governmental commitments toward structured and healthy urban planning.

Bane or boon regarding urbanicity and psychotic spectrum disorders: a scoping review of current evidence

PURPOSE OF REVIEW

This review aims to provide an update on the association between urbanization and psychotic spectrum disorders, focusing on specific aspects of the urban environment that could be a bane or boon for the risk of psychosis.

RECENT FINDINGS

Majority of the included studies support previous evidence suggesting that urbanization is linked to a higher risk of psychotic experiences and psychotic spectrum disorders. A small minority, however, have also found specific factors in the urban environment that could give rise to positive outcomes, such as better social functioning and lower mortality rates in psychotic spectrum disorders, or mitigate the risks associated with urbanization. The perception of the urban environment was also an important factor that increased or mitigated stress levels in patients with psychosis, which in turn affected their susceptibility to psychotic symptoms.

SUMMARY

Specific aspects of the urban environment such as the availability and density of greenspaces are crucial for mitigating the effect of urbanization on risk of psychotic spectrum disorders, and should be incorporated into urban planning. At the same time, there is a need to further explore how modifiable risk factors of the urban environment such as air and noise pollution can be minimized to allow for more liveable cities in the context of psychotic spectrum conditions.

Inequalities in the Incidence of Psychotic Disorders Among Racial and Ethnic Groups

OBJECTIVE

The authors examined recent trends in incidence of psychotic disorders, demographic characteristics, and comorbid psychiatric and medical conditions among six racial/ethnic groups.

METHOD

A retrospective cohort study design was used to examine the incidence of psychotic disorders across race/ethnicity groups and comorbid psychiatric and medical conditions among members of Kaiser Permanente Northern California from 2009 to 2019 (N=5,994,758). Poisson regression was used to assess changes in annual incidence, and Cox proportional hazards and logistic regression models adjusted for age and sex were used to test correlates and consequences.

RESULTS

Overall, the incidence of nonaffective psychotic disorders decreased slightly over the study period. Compared with White members, the risk of nonaffective psychosis diagnosis was higher among Black (hazard ratio=2.13, 95% CI=2.02-2.24) and American Indian or Alaskan Native (AIAN) (hazard ratio=1.85, 95% CI=1.53-2.23) members and lower among Asian (hazard ratio=0.72, 95% CI=0.68-0.76) and Hispanic (hazard ratio=0.91, 95% CI=0.87-0.96) members, as well as those whose race/ethnicity was categorized as "other" (hazard ratio=0.92, 95% CI=0.86-0.99). Compared with White members, the risk of affective psychosis diagnosis adjusted for age and sex was higher among Black (hazard ratio=1.76, 95% CI=1.62-1.91), Hispanic (hazard ratio=1.09, 95% CI=1.02-1.16), and AIAN (hazard ratio=1.38, 95% CI=1.00-1.90) members and lower among Asian (hazard ratio=0.77, 95% CI=0.71-0.83), Native Hawaiian or other Pacific Islander (hazard ratio=0.69, 95% CI=0.48-0.99), and "other" (hazard ratio=0.86, 95% CI=0.77-0.96) members. Psychotic disorders were associated with significantly higher odds of suicide (odds ratio=2.65, 95% CI=2.15-3.28), premature death (odds ratio=1.30, 95% CI=1.22-1.39), and stroke (odds ratio=1.64, 95% CI=1.55-1.72) and lower odds of health care utilization (odds ratio=0.44, 95% CI=0.42-0.47).

CONCLUSIONS

This study demonstrates racial and ethnic variation in incident psychotic disorder diagnoses in the United States, compared with non-Hispanic Whites. Individuals diagnosed with psychosis face a greater burden of other negative health outcomes and lower odds of health care utilization, reflecting personal and economic impacts. Identifying risk factors for elevated rates and protective influences in subgroups can inform strategies for prevention and interventions to ameliorate severe consequences of psychotic syndromes.

A public early intervention approach to first-episode psychosis: Treated incidence over 7 years in the Emilia-Romagna region

AIM

To estimate the treated incidence of individuals with first-episode psychosis (FEP) who contacted the Emilia-Romagna public mental healthcare system (Italy); to examine the variability of incidence and user characteristics across centres and years.

METHODS

We computed the raw treated incidence in 2013-2019, based on FEP users aged 18-35, seen within or outside the regional program for FEP. We modelled FEP incidence across 10 catchment areas and 7 years using Bayesian Poisson and Negative Binomial Generalized Linear Models of varying complexity. We explored associations between user characteristics, study centre and year comparing variables and socioclinical clusters of subjects.

RESULTS

Thousand three hundred and eighteen individuals were treated for FEP (raw incidence: 25.3 / 100.000 inhabitant year, IQR: 15.3). A Negative Binomial location-scale model with area, population density and year as predictors found that incidence and its variability changed across centres (Bologna: 36.55; 95% CrI: 30.39-43.86; Imola: 3.07; 95% CrI: 1.61-4.99) but did not follow linear temporal trends or density. Centers were associated with different user age, gender, migrant status, occupation, living conditions and cluster distribution. Year was associated negatively with HoNOS score (R = -0.09, p < .001), duration of untreated psychosis (R = -0.12, p < .001) and referral type.

CONCLUSIONS

The Emilia-Romagna region presents a relatively high but variable incidence of FEP across areas, but not in time. More granular information on social, ethnic and cultural factors may increase the level of explanation and prediction of FEP incidence and characteristics, shedding light on social and healthcare factors influencing FEP.