Risk of schizophrenia and minority status: a comparison of the Swedish-speaking minority and the Finnish-speaking majority in Finland

Social defeat predicts the emergence of psychotic-like experiences through the effects on aberrant salience: insights from a network analysis of longitudinal data

BACKGROUND

Psychotic-like experiences (PLEs) are subclinical phenomena that often precede the onset of psychosis and occur in various mental disorders. Social determinants of psychosis and PLEs are important and have been operationalized within the social defeat (SD) hypothesis. The SD hypothesis posits that low social status and exposure to repeated humiliation can lead to imbalanced dopamine neuron activity, and thus increased risk of psychosis. We aimed to assess the role of dynamic interactions between SD components in shaping the occurrence of PLEs using a network analysis.

METHODS

A total of 2241 non-clinical, young adults were assessed at baseline and invited for reassessment after a 6-month follow-up. Self-reports recording the occurrence of PLEs, aberrant salience (AS), depressive, and anxiety symptoms as well as SD characteristics (socioeconomic status, minority status, humiliation, perceived constraints, and domain control) were administered. Two networks were analyzed (the first one covering all baseline measures and the second one with the baseline SD components and follow-up measures of AS and psychopathology).

RESULTS

The SD components were not directly connected to the measures of PLEs in both networks. However, in both networks, SD components were connected to PLEs through a mediating effect of AS. Among SD components, humiliation had the highest bridge centrality across three predefined communities of variables (SD; depressive and anxiety symptoms; AS, and PLEs).

CONCLUSIONS

The findings indicate that SD might make individuals vulnerable to develop PLEs through the mediating effects of AS. Among SD components, humiliation might play the most important role in the development of PLEs.

Geographical variation in treated psychotic and other mental disorders in Finland by region and urbanicity

PURPOSE

In Finland, prevalence of schizophrenia is higher in the eastern and northern regions and co-occurs with the distribution of schizophrenia polygenic risk scores. Both genetic and environmental factors have been hypothesized to contribute to this variation. We aimed to examine the prevalence of psychotic and other mental disorders by region and degree of urbanicity, and the impacts of socio-economic adjustments on these associations.

METHODS

Nationwide population registers from 2011 to 2017 and healthcare registers from 1975 to 2017. We used 19 administrative and three aggregate regions based on the distribution of schizophrenia polygenic risk scores, and a seven-level urban-rural classification. Prevalence ratios (PRs) were calculated by Poisson regression models and adjusted for gender, age, and calendar year (basic adjustments), and Finnish origin, residential history, urbanicity, household income, economic activity, and physical comorbidity (additional adjustments) on an individual level. Average marginal effects were used to visualize interaction effects between region and urbanicity.

RESULTS

A total of 5,898,180 individuals were observed. All mental disorders were slightly more prevalent (PR 1.03 [95% CI, 1.02-1.03]), and psychotic disorders (1.11 [1.10-1.12]) and schizophrenia (1.19 [1.17-1.21]) considerably more prevalent in eastern and northern than in western coastal regions. After the additional adjustments, however, the PRs were 0.95 (0.95-0.96), 1.00 (0.99-1.01), and 1.03 (1.02-1.04), respectively. Urban residence was associated with increased prevalence of psychotic disorders across all regions (adjusted PR 1.21 [1.20-1.22]).

CONCLUSION

After adjusting for socioeconomic and sociodemographic factors, the within-country distribution of mental disorders no longer followed the traditional east-west gradient. Urban-rural differences, on the other hand, persisted after the adjustments.

"Blessed are the Nations with High Levels of Schizophrenia": National Level Schizophrenia Prevalence and Its Relationship with National Levels of Religiosity

Schizophrenia is correlated with religious delusions but, heretofore, the relationship between schizophrenia prevalence and religiosity has not been explored at the national level. Examining this relationship, we find that national level schizophrenia prevalence is correlated with national level religiosity and strongly negatively correlated with national level atheism across 125 countries. When controlling for cognitive performance and economic development in multiple regression analyses, the proportion of the variance explained was 2.9% (p < .005) for Religiousness and 5.1% for Atheism (p < .00005). Alternative causal interpretations of this association are discussed.

The ethnic density effect in psychosis: a systematic review and multilevel meta-analysis

BACKGROUND

An 'ethnic' or 'group' density effect in psychosis has been observed, whereby the risk of psychosis in minority group individuals is inversely related to neighbourhood-level proportions of others belonging to the same group. However, there is conflicting evidence over whether this effect differs between minority groups and limited investigation into other moderators.

AIMS

To conduct a comprehensive systematic review and meta-analysis of the group density effect in psychosis and examine moderators.

METHOD

Four databases were systematically searched. A narrative review was conducted and a three-level meta-analysis was performed. The potential moderating effect of crudely and specifically defined minority groups was assessed. Country, time, area size and whether studies used clinical or non-clinical outcomes were also tested as moderators.

RESULTS

Thirty-two studies were included in the narrative review and ten in the meta-analysis. A 10 percentage-point decrease in own-group density was associated with a 20% increase in psychosis risk (OR = 1.20, 95% CI 1.09-1.32, P < 0.001). This was moderated by crudely defined minority groups (F6,68 = 6.86, P < 0.001), with the strongest associations observed in Black populations, followed by a White Other sample. Greater heterogeneity was observed when specific minority groups were assessed (F25,49 = 7.26, P < 0.001).

CONCLUSIONS

This is the first review to provide meta-analytic evidence that the risk of psychosis posed by lower own-group density varies across minority groups, with the strongest associations observed in Black individuals. Heterogeneity in effect sizes may reflect distinctive social experiences of specific minority groups. Potential mechanisms are discussed, along with the implications of findings and suggestions for future research.

Social capital and psychosis: a scoping review

PURPOSE

Social capital has been studied as a risk factor for psychotic disorders. The purpose of this scoping review was to scope the literature and synthesize findings on the association between social capital and psychosis.

METHODS

Three electronic databases were searched to identify relevant studies. Studies were included if they examined the association between social capital and either diagnosed psychotic disorders or symptoms of psychosis.

RESULTS

Of 191 studies reviewed, 12 met the inclusion criteria. Ten studies measured social capital at the ecological level. Seven studies focused on risk of psychotic disorders or symptoms of psychosis, three studies focused on course of psychotic illness, and two studies focused on both risk and course of illness. A variety of social capital measures were used including scales, surveys, and census-based measures. The association between social capital and both the incidence of psychosis and patterns of service use varied based on measures used and study population. There was no association between social capital and recovery or duration of untreated illness.

CONCLUSIONS

Prior literature has examined the impact of social capital on the incidence of psychotic disorders, as well as symptoms and course of illness. Based on the scant literature to date, it is difficult to make firm conclusions regarding the role of social capital in psychotic disorders. Heterogeneous measures of social capital make comparisons between studies challenging. Further specificity in measuring and defining dimensions of social capital is required for meaningful study of social capital and its association with psychotic disorders.

Antipsychotic medication use among working-age first-generation migrants resident in Finland: An administrative data linkage study

Aims: Higher incidence of psychotic disorders in high-income countries for migrants compared with the settled majority has been well established. However, it is less clear to what extent different migrants groups have accessed and utilised mental health care. This study aimed to identify the hazard of antipsychotic medication use in the largest migrant groups in Finland, compared with a Finnish-born comparison group, using high quality datasets maintained by Statistics Finland and Social Insurance Institution Finland, and linking socio-demographic and -economic characteristics to antipsychotic prescription purchases. Methods: The study draws on a representative sample of 33% of the adult working-age population of Finland in 2005 ( n = 1,059,426, 50.2% male, 2.5% migrant). The use of antipsychotic drugs was followed-up from 2005 to 2014. Results: The results show that the hazard of antipsychotic medication purchases differed between migrant groups, with a higher hazard for migrants from North Africa and the Middle East before socio-economic adjustment (men HR 1.19, 95% CI 1.04–1.37; women HR 1.37, 95% CI 1.12–1.66), and a lower hazard for all migrant groups after adjustment for socio-economic characteristics compared with the Finland-born population. Conclusions: The findings suggest that attention should be paid to the lower use of medication for psychotic disorders in some migrant groups, as well as the potential role of social disadvantage for migrants from North Africa and Middle East.

Search for protective factors for psychosis - a population-based sample with special interest in unaffected individuals with parental psychosis

AIM

To find factors that are associated with not having psychotic illness in a prospective general population sample, with a special interest in individuals with parental psychosis.

METHODS

Data from the Northern Finland Birth Cohort 1966 (n = 10 458) and several registers were used to detect individuals with and without parental psychosis. Altogether, 594 persons had parent(s) with psychosis and 48 of them also had psychosis subsequently. Variables related to pregnancy and birth, family and childhood, health and habits in adolescence, school performance and physical activity were studied to identify determinants of unaffected status among individuals with and without parental psychosis.

RESULTS

In the parental psychosis group, the unaffected persons had more likely a mother who was non-depressed during pregnancy, and who worked outside the home or studied than among those who developed psychosis.

CONCLUSIONS

Protective factors for psychosis were surprisingly few in this sample. These factors were related to the mother's non-depressed mood and the mother's work outside the home or studies. This could relate to better health and functioning of a mother. This work highlights the need for more research on protective factors for psychosis in order to identify methods for prevention of psychosis.

Impact of social disadvantage and parental offending on rates of criminal offending among offspring of women with severe mental illness

OBJECTIVE

Children of parents with severe mental illness have an increased risk of offending. Studies suggest that risk factors such as parental offending and social disadvantage may be associated with the increased risk. This paper assesses the impact of these risk factors on offending rates in the offspring of women with severe mental illness compared to offspring of unaffected women.

METHODS

This is part of a longitudinal record-linked whole-population study of 467,945 children born in Western Australia from 1980 to 2001 to mothers with severe mental illness and mothers with no recorded psychiatric illness. These data were linked to Western Australia corrective services data producing a dataset of 12,999 people with at least one offence (3.7% of birth cohort). Cox proportional hazard was used to calculate incidence rate ratios of offspring offending.

RESULTS

The offending rate for offspring of mothers with severe mental illness (cases) was almost three times the rate for offspring of unaffected mothers (comparison) with an unadjusted incidence rate ratio of 2.75 (95% confidence interval: [2.58, 2.93]). Adjusting for sex, indigenous status, socio-economic status and geographical remoteness reduced the rate ratio by 24% to incidence rate ratio 2.10, 95% confidence interval: [1.97, 2.23]. Adjusting for parental offending further reduced the rate ratio by 23% to incidence rate ratio 1.62, 95% confidence interval: [1.52, 1.72]. The mean age at first recorded offence was significantly lower for cases compared to comparison offspring.

CONCLUSION

Children of mothers with a severe mental illness have a higher rate of offending than children of unaffected mothers, and social disadvantage and parental offending have a major impact on this rate. Services supporting these vulnerable children need to focus on improving the social environment in which they and their families live in.

Psychotic-like experiences and correlation with childhood trauma and other socio-demographic factors: A cross-sectional survey in adolescence and early adulthood in China

Psychotic-like experiences (PLEs) in adolescence are found to be risk factors for later mental disorders. Previous research has also found that childhood trauma has a positive correlation with mental health problems. However, few studies have focused on the relationship between them, especially in adolescence and early adulthood. A total of 9122 students (age between 10 and 23.3) were surveyed and assessed with the positive and depressive subscales of the Community Assessment of Psychic Experiences and the Trauma History Questionnaire. A total of 20.7% students experienced frequent PLEs, 17.5% had frequent delusional experiences, and 7.6% had frequent hallucinatory experiences. Only a small portion of this sample experienced frequent PLEs, associated with more types of PLEs, more distress, and more depressive experiences. Several socio-demographic factors were associated with frequent PLEs in this sample, which could be further examined in future prevention studies. Students with frequent PLEs experienced significantly higher impact from trauma events, both at the time of the events and in the present, indicating a possible reciprocal effect between childhood trauma and PLEs. The impact of childhood trauma played an important role in the relationship between childhood trauma and PLEs.

Sense of mastery differences between working-age Swedish- and Finnish-speaking Finns: a population-based study

AIM

To examine the probability of a high sense of mastery in a population-representative sample of working-age people and to study the differences in mastery between Finnish-speaking and Swedish-speaking Finns in particular.

METHODS

The data originates from the Western Finland Mental Health Surveys (2008-2014). Associations between sense of mastery and language groups were analyzed with logistic regressions.

RESULTS

Swedish-speaking Finns have a higher sense of mastery and the association is mediated by social support. Moreover, a difference in a high sense of mastery is found between Swedish- and Finnish-speaking married women that are outside the labor market.

CONCLUSIONS

Our findings imply that Finnish-speaking women that are outside the labor market, e.g. on maternity leave or taking care of the household, should be recognized in health and social care services as a group that can benefit from additional support.

Paternal occupational lead exposure and offspring risks for schizophrenia

This register-based cohort study investigated whether paternal occupational exposure to inorganic lead was related to offspring risk for schizophrenia spectrum disorder (SSD). Exposed men (n=11,863) were identified from blood lead measurements taken at the Finnish Institute of Occupational Health in 1973-1983. Data on mothers and their offspring born from 1972-1984 were obtained from the national Population Information System. Two population comparison offspring for each exposed offspring were matched on date of birth, sex and area (n=23,720). SSD cases were identified from The Finnish Hospital Discharge Register. Hazard ratios of SSD between exposed groups were analyzed using conditional proportional hazards regression, adjusted for parental history of psychoses, parental ages, language of offspring, father's employment, and father's self-employment. After 26-38years of follow up, there were no significant differences in the incidence of schizophrenia, either between the offspring of exposed (188/11,863; 1.6%) and unexposed fathers (347/23,720; 1.5%) or based on blood lead levels (adjusted hazard ratios (aHR): 0.97, CI 0.52-1.83, 1.25, CI 0.85-1.82, 0.90, CI 0.54-1.49, and 1.38, CI 0.65-2.92 for lead categories <0.5, 0.5-0.9, 1.0-1.4, and ≥1.5μmol/L, respectively, as compared to population comparison). Parental psychosis, paternal age and offspring language were associated with offspring risk. The findings suggest that paternal exposure to lead is not a risk factor for schizophrenia in offspring. However, the majority of exposed fathers had low-level exposure, and we cannot exclude the possibility of an effect for higher exposures to lead.

Incidence of psychotic disorders among first-generation immigrants and refugees in Ontario

BACKGROUND

Evidence suggests that migrant groups have an increased risk of psychotic disorders and that the level of risk varies by country of origin and host country. Canadian evidence is lacking on the incidence of psychotic disorders among migrants. We sought to examine the incidence of schizophrenia and schizoaffective disorders in first-generation immigrants and refugees in the province of Ontario, relative to the general population.

METHODS

We constructed a retrospective cohort that included people aged 14-40 years residing in Ontario as of Apr. 1, 1999. Population-based administrative data from physician billings and hospital admissions were linked to data from Citizenship and Immigration Canada. We used Poisson regression models to calculate age- and sex-adjusted incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for immigrant and refugee groups over a 10-year period.

RESULTS

In our cohort (n = 4,284,694), we found higher rates of psychotic disorders among immigrants from the Caribbean and Bermuda (IRR 1.60, 95% CI 1.29-1.98). Lower rates were found among immigrants from northern Europe (IRR 0.50, 95% CI 0.28-0.91), southern Europe (IRR 0.60, 95% CI 0.41-0.90) and East Asia (IRR 0.56, 95% CI 0.41-0.78). Refugee status was an independent predictor of risk among all migrants (IRR 1.27, 95% CI 1.04-1.56), and higher rates were found specifically for refugees from East Africa (IRR 1.95, 95% CI 1.44-2.65) and South Asia (IRR 1.51, 95% CI 1.08-2.12).

INTERPRETATION

The differential pattern of risk across ethnic subgroups in Ontario suggests that psychosocial and cultural factors associated with migration may contribute to the risk of psychotic disorders. Some groups may be more at risk, whereas others are protected.