The role of migration and social environments in the risk of psychotic disorders

Background: While numerous studies have demonstrated elevated psychosis risk in migrant groups, adequate explanations for this pattern have not been elucidated. The elevated burden of psychotic disorders represents a pressing public mental health priority, and thus understanding the determinants of increased risk is important in addressing this disparity. Objective: To determine how migration-related factors and the social environment affect the risk of developing psychotic disorders among migrants and their children. In order to investigate what drives elevated psychosis risk, my studies focused on migration-related factors, including region, age-at-migration, and family network, and aspects of the post-migratory environment, including neighbourhood ethnic density. Methods: I linked multiple Swedish population registers to conduct three longitudinal cohort studies. In Chapter 3, I investigated if risk of schizophrenia, schizoaffective disorder, and bipolar disorders varied by migrant status, region of origin, and age-at-migration. I examined the role of family network in psychosis risk amongst migrants in Chapter 4. Finally, I assessed how neighbourhood ethnic density affects psychosis risk in Chapter 5. I used Cox proportional hazards modelling throughout, with multilevel extension in Chapter 5. Results: Chapter 3 revealed increased risk of psychiatric disorders associated with migrant status was specific to psychotic disorders, with exact risk dependent on region of origin. Risk for psychotic disorders was elevated across most ages-at-migration, while risk of non-psychotic bipolar disorder was lower for all ages-of-migration except infancy. Chapter 4 showed that family networks at the time of migration differentially affected the risk of developing non-affective psychotic disorders for males and females. I found that the presence of family during migration was protective for females but increased risk among males. In Chapter 5, I found evidence that as own-group ethnic density increased, risk of non-affective psychosis decreased. Conclusions: Taken together, this research highlighted factors at the individual (e.g. migration status, region of origin, age-at-migration), family (family networks), and neighbourhood (ethnic density) levels that affected psychosis risk in migrants and their children. These studies demonstrated distinct patterns of risk and add to the body of knowledge around the social and structural explanations for psychotic disorders. These studies contribute to the growing body of evidence demonstrating the importance of the social environment in the aetiology of psychotic disorders and opens lines of inquiry for future research in this field

The Longitudinal Impact of Social Media Use on UK Adolescents' Mental Health: Longitudinal Observational Study

BACKGROUND: Cross-sectional studies have found a relationship between social media use and depression and anxiety in young people. However, few longitudinal studies using representative data and mediation analysis have been conducted to understand the causal pathways of this relationship. OBJECTIVE: This study aims to examine the longitudinal relationship between social media use and young people's mental health and the role of self-esteem and social connectedness as potential mediators. METHODS: The sample included 3228 participants who were 10- to 15-year-olds from Understanding Society (2009-2019), a UK longitudinal household survey. The number of hours spent on social media was measured on a 5-point scale from "none" to "7 or more hours" at the ages of 12-13 years. Self-esteem and social connectedness (number of friends and happiness with friendships) were measured at the ages of 13-14 years. Mental health problems measured by the Strengths and Difficulties Questionnaire were assessed at the ages of 14-15 years. Covariates included demographic and household variables. Unadjusted and adjusted multilevel linear regression models were used to estimate the association between social media use and mental health. We used path analysis with structural equation modeling to investigate the mediation pathways. RESULTS: In adjusted analysis, there was a nonsignificant linear trend showing that more time spent on social media was related to poorer mental health 2 years later (n=2603, β=.21, 95% CI 0.43 to 0.84; P=.52). In an unadjusted path analysis, 68% of the effect of social media use on mental health was mediated by self-esteem (indirect effect, n=2569, β=.70, 95% CI 0.15-1.30; P=.02). This effect was attenuated in the adjusted analysis, and it was found that self-esteem was no longer a significant mediator (indirect effect, n=2316, β=.24, 95% CI 0.12 to 0.66; P=.22). We did not find evidence that the association between social media and mental health was mediated by social connectedness. Similar results were found in imputed data. CONCLUSIONS: There was little evidence to suggest that more time spent on social media was associated with later mental health problems in UK adolescents. This study shows the importance of longitudinal studies to examine this relationship and suggests that prevention strategies and interventions to improve mental health associated with social media use could consider the role of factors like self-esteem

Trajectories of housing affordability and mental health problems: a population-based cohort study

PURPOSE: With housing costs increasing faster than incomes and a limited supply of social housing options, many households face unaffordable housing. Housing affordability problems may negatively impact mental health; however, longitudinal evidence is limited. This study investigates the association between trajectories of housing affordability problems and mental health. METHODS: We used data from 30,025 households from Understanding Society, a longitudinal household survey from the UK. Participants spending 30% or more of household income on housing were categorised as facing housing affordability problems. We estimated group-based trajectories of housing affordability problems from 9 waves of data (2009-2019). We used linear regression to calculate the association between the trajectories and mental health problems, as measured by General Health Questionnaire (GHQ) score in Wave 10 (2018-2020). RESULTS: We found six distinct trajectories of housing affordability problems. Those in the 'stable low' group had a consistently low probability of affordability problems, whilst those in 'high falling' group had a sustained high probability in the earlier waves of the study, subsequently decreasing over time. The adjusted analysis showed that trajectory group membership over the first nine waves of data predicted GHQ score in 2018-2020 (Wave 10). Compared to the 'stable low' group, those in the 'high falling' group had a GHQ score that was 1.06 (95% CI 0.53-1.58) points higher. CONCLUSION: This study provides evidence that sustained exposure to housing affordability problems is associated with long-term worse mental health, even in the absence of more recent problems

Triple trauma, double uncertainty, and a singular imperative to address the mental health crises within asylum-seekers and refugees system: a commentary on Hvidtfeldt et al. (2021)

The current geo-political crisis around the world is a stark reminder of the impact of war and displacement on the lives of individuals. In 2020, the UN Refugee Agency estimated that over 1% of the world’s population were forcibly displaced persons (82.4 million people) including 26.4 million refugees and 4.1 million asylum seekers [1]. Estimates suggest that the number of forcibly displaced people has continued to rise over the past year, reaching 84 million by mid-2021, and rising with ongoing conflicts in Syria, Afghanistan, South Sudan, Ukraine, and more. The rising number of forcibly displaced people adds urgency to ensuring the human rights, health, and dignity of those forced to leave their homes

Social Deprivation and Population Density Trajectories Before and After Psychotic Disorder Diagnosis

IMPORTANCE: People with psychosis are more likely to be born and live in densely populated and socioeconomically deprived environments, but it is unclear whether these associations are a cause or consequence of disorder. OBJECTIVE: To investigate whether trajectories of exposure to deprivation and population density before and after diagnosis are associated with psychotic disorders or nonpsychotic bipolar disorder. DESIGN, SETTING, AND PARTICIPANTS: This nested case-control study included all individuals born in Sweden between January 1, 1982, and December 31, 2001, diagnosed for the first time with an International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) psychotic disorder or nonpsychotic bipolar disorder between their 15th birthday and cohort exit (December 31, 2016). One sex- and birth year-matched control participant per case was selected. Data analysis was performed from July 2021 to June 2023. EXPOSURES: The main exposures were quintiles of neighborhood-level deprivation and population density each year from birth to age 14 years and from first diagnosis until cohort exit. MAIN OUTCOMES AND MEASURES: The main outcomes were the odds of a serious mental illness outcome associated with trajectories of deprivation and population density, before and after diagnosis in cases. Group-based trajectory modeling was used to derive trajectories of each exposure in each period. Logistic regression was used to examine associations with outcomes. RESULTS: A total of 53 458 individuals (median [IQR] age at diagnosis in case patients, 23.2 [15.0-34.8] years; 30 746 [57.5%] female), including 26 729 case patients and 26 729 control participants, were studied. From birth to early adolescence, gradients were observed in exposure to deprivation and population density trajectories during upbringing and psychotic disorder, with those in the most vs least deprived (adjusted odds ratio [AOR], 1.17; 95% CI, 1.08-1.28) and most vs least densely populated (AOR, 1.49; 95% CI, 1.34-1.66) trajectories at greatest risk. A strong upward mobility trajectory to less deprived neighborhoods was associated with similar risk to living in the least deprived trajectory (AOR, 1.01; 95% CI, 0.91-1.12). Only 543 case patients (2.0%) drifted into more deprived areas after diagnosis; people with psychotic disorder were more likely to belong to this trajectory (AOR, 1.38; 95% CI, 1.16-1.65) or remain in the most deprived trajectory (AOR, 1.36; 95% CI, 1.24-1.48) relative to controls. Patterns were similar for nonpsychotic bipolar disorder and deprivation but weaker for population density. CONCLUSIONS AND RELEVANCE: In this case-control study, greater exposure to deprivation during upbringing was associated with increased risk of serious mental illness, but upward mobility mitigated this association. People with serious mental illness disproportionately remained living in more deprived areas after diagnosis, highlighting issues of social immobility. Prevention and treatment should be proportionately located in deprived areas according to need

The gender dimensions of mental health during the Covid-19 pandemic: A path analysis

BACKGROUND: The Covid-19 pandemic has had a substantial population mental health impact, with evidence indicating that mental health has deteriorated in particular for women. This gender difference could be explained by the distinct experiences of women during the pandemic, including the burden of unpaid domestic labour, changes in economic activity, and experiences of loneliness. This study investigates potential mediators in the relationship between gender and mental health during the first wave of the Covid-19 pandemic in the UK. METHODS: We used data from 9,351 participants of Understanding Society, a longitudinal household survey from the UK. We conducted a mediation analysis using structural equation modelling to estimate the role of four mediators, measured during the first lockdown in April 2020, in the relationship between gender and mental health in May and July 2020. Mental health was measured with the 12-item General Health Questionnaire (GHQ-12). Standardized coefficients for each path were obtained, as well as indirect effects for the role of employment disruption, hours spent on housework, hours spent on childcare, and loneliness. RESULTS: In a model controlling for age, household income and pre-pandemic mental health, we found that gender was associated with all four mediators, but only loneliness was associated with mental health at both time points. The indirect effects showed strong evidence of partial mediation through loneliness for the relationship between gender and mental health problems; loneliness accounted for 83.9% of the total effect in May, and 76.1% in July. No evidence of mediation was found for housework, childcare, or employment disruption. CONCLUSION: The results suggest that the worse mental health found among women during the initial period of the Covid-19 pandemic is partly explained by women reporting more experiences of loneliness. Understanding this mechanism is important for prioritising interventions to address gender-based inequities that have been exacerbated by the pandemic

Substance use disorders in refugee and migrant groups in Sweden: A nationwide cohort study of 1.2 million people

Background: Refugees are at higher risk of some psychiatric disorders, including post-traumatic stress disorder (PTSD) and psychosis, compared with other non-refugee migrants and the majority population. However, it is unclear whether this also applies to substance use disorders, which we investigated in a national register cohort study in Sweden. We also investigated whether risk varied by region of origin, age at migration, time in Sweden, and diagnosis of PTSD. Methods and findings: Using linked Swedish register data, we followed a cohort born between 1984 and 1997 from their 14th birthday or arrival in Sweden, if later, until an International Classification of Diseases, 10th revision (ICD-10), diagnosis of substance use disorder (codes F10.X–19.X), emigration, death, or end of follow-up (31 December 2016). Refugee and non-refugee migrants were restricted to those from regions with at least 1,000 refugees in the Swedish registers. We used Cox proportional hazards regression to estimate unadjusted and adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) in refugee and non-refugee migrants, compared with Swedish-born individuals, for all substance use disorders (F10.X–19.X), alcohol use disorders (F10.X), cannabis use disorders (F12.X), and polydrug use disorders (F19.X). In adjusted analyses, we controlled for age, sex, birth year, family income, family employment status, population density, and PTSD diagnosis. Our sample of 1,241,901 participants included 17,783 (1.4%) refugee and 104,250 (8.4%) non-refugee migrants. Refugees' regions of origin were represented in proportions ranging from 6.0% (Eastern Europe and Russia) to 41.4% (Middle East and North Africa); proportions of non-refugee migrants' regions of origin ranged from 11.8% (sub-Saharan Africa) to 33.7% (Middle East and North Africa). These groups were more economically disadvantaged at cohort entry (p < 0.001) than the Swedish-born population. Refugee (aHR: 0.52; 95% CI 0.46–0.60) and non-refugee (aHR: 0.46; 95% CI 0.43–0.49) migrants had similarly lower rates of all substance use disorders compared with Swedish-born individuals (crude incidence: 290.2 cases per 100,000 person-years; 95% CI 287.3–293.1). Rates of substance use disorders in migrants converged to the Swedish-born rate over time, indicated by both earlier age at migration and longer time in Sweden. We observed similar patterns for alcohol and polydrug use disorders, separately, although differences in cannabis use were less marked; findings did not differ substantially by migrants’ region of origin. Finally, while a PTSD diagnosis was over 5 times more common in refugees than the Swedish-born population, it was more strongly associated with increased rates of substance use disorders in the Swedish-born population (aHR: 7.36; 95% CI 6.79–7.96) than non-refugee migrants (HR: 4.88; 95% CI 3.71–6.41; likelihood ratio test [LRT]: p = 0.01). The main limitations of our study were possible non-differential or differential under-ascertainment (by migrant status) of those only seen via primary care and that our findings may not generalize to undocumented migrants, who were not part of this study. Conclusions: Our findings suggest that lower rates of substance use disorders in migrants and refugees may reflect prevalent behaviors with respect to substance use in migrants’ countries of origin, although this effect appeared to diminish over time in Sweden, with rates converging towards the substantial burden of substance use morbidity we observed in the Swedish-born population.publishedVersio

Neighborhood-level predictors of age-at-first-diagnosis of psychotic disorders: a Swedish register-based cohort study

The relationship between neighborhood-level factors and the incidence of psychotic disorders is well established. However, it is unclear whether neighborhood characteristics are also associated with age-at-first-diagnosis of these disorders. We used linked Swedish register data to identify a cohort of persons first diagnosed with an ICD-10 non-affective or affective psychotic disorder (F20-33) between 1997 and 2016. Using multilevel mixed-effect linear modelling, we investigated whether neighborhood deprivation and population density at birth were associated with age-at-first diagnosis of a psychotic disorder. Our final cohort included 13,440 individuals, with a median age-at-first-diagnosis of 21.8 years for women (interquartile range [IQR]: 19.0-25.5) and 22.9 years for men (IQR: 20.1-26.1; p<.0001). In an unadjusted model, we found no evidence of an association between neighborhood deprivation and age-at-first-diagnosis of psychotic disorder (p=.07). However, after multivariable adjustment, age-at-first-diagnosis increased by .13 years (95% CI: .05 to .21; p=.002) for a one standard deviation increase in neighborhood deprivation. This was equivalent to a later diagnosis of 47 days (95% CI: 18 to 77). We found no evidence of a different relationship for non-affective versus affective psychoses (LRT χ2(1) = .14; p=.71). Population density was not associated with age-at-first-diagnosis in unadjusted (p=.81) or adjusted (p=.85) models. Later age-at-first-diagnosis for individuals born in more deprived neighborhoods suggests structural barriers to accessing equitable psychiatric care

Measuring social exclusion and its distribution in England

Background: Social exclusion is a multidimensional concept referring processes which restrict the ability of individuals or groups to participate fully in society. While social exclusion has been used to explore patterns of disadvantage, it has been difficult to measure. Thus, we aimed to use population-based data to measure social exclusion and its constituent domains and to describe its distribution in England. Methods: We used data from Understanding Society in 2009/2010 develop a multidimensional measurement approach, replicated in 2018/2019. We defined five domains of social exclusion from the literature and expert consultation: material, relational, political, digital, and structural. In both waves, we identified measures for each domain, then conducted principal component analysis to identify the components. We generated domain scores and an overall social exclusion score. We described the distribution of social exclusion and its domains by sex, region, age, and ethnicity. Results: We found the level of social exclusion was higher in the youngest age group and decreased by age. We found elevated levels of overall social exclusion for ethnic minoritised groups including African, Arab, and Caribbean groups compared to White British groups. We found distinct patterns within each domain. Discussion: We developed an overall measure of social exclusion with five domains, and finding distinct patterns of social exclusion by age, ethnicity, and region which varied across domain. These findings suggest that attention should be paid to the separate domains due to different population distributions. This measurement approach moves beyond conceptual discussions of social exclusion and demonstrates the utility of a quantitative measure of social exclusion for use in health and social research

The effect of immigration policy reform on mental health in people from minoritised ethnic groups in England: an interrupted time series analysis of longitudinal data from the UK Household Longitudinal Study cohort

Background: In 2012, the UK Government announced a series of immigration policy reforms known as the hostile environment policy, culminating in the Windrush scandal. We aimed to investigate the effect of the hostile environment policy on mental health for people from minoritised ethnic backgrounds. We hypothesised that people from Black Caribbean backgrounds would have worse mental health relative to people from White ethnic backgrounds after the Immigration Act 2014 and the Windrush scandal media coverage in 2017, since they were particularly targeted. Methods: Using data from the UK Household Longitudinal Study, we performed a Bayesian interrupted time series analysis, accounting for fixed effects of confounders (sex, age, urbanicity, relationship status, number of children, education, physical or mental health impairment, housing, deprivation, employment, place of birth, income, and time), and random effects for residual temporal and spatial variation. We measured mental ill health using a widely used, self-administered questionnaire on psychological distress, the 12-item General Health Questionnaire (GHQ-12). We compared mean differences (MDs) and 95% credible intervals (CrIs) in mental ill health among people from minoritised ethnic groups (Black Caribbean, Black African, Indian, Bangladeshi, and Pakistani) relative to people of White ethnicity during three time periods: before the Immigration Act 2014, after the Immigration Act 2014, and after the start of the Windrush scandal media coverage in 2017. Findings: We included 58 087 participants with a mean age of 45·0 years (SD 34·6; range 16–106), including 31 168 (53·6%) female and 26 919 (46·3%) male participants. The cohort consisted of individuals from the following ethnic backgrounds: 2519 (4·3%) Black African, 2197 (3·8%) Black Caribbean, 3153 (5·4%) Indian, 1584 (2·7%) Bangladeshi, 2801 (4·8%) Pakistani, and 45 833 (78·9%) White. People from Black Caribbean backgrounds had worse mental health than people of White ethnicity after the Immigration Act 2014 (MD in GHQ-12 score 0·67 [95% CrI 0·06–1·28]) and after the 2017 media coverage (1·28 [0·34–2·21]). For Black Caribbean participants born outside of the UK, mental health worsened after the Immigration Act 2014 (1·25 [0·11–2·38]), and for those born in the UK, mental health worsened after the 2017 media coverage (2·00 [0·84–3·15]). We did not observe effects in other minoritised ethnic groups. Interpretation: Our finding that the hostile environment policy worsened the mental health of people from Black Caribbean backgrounds in the UK suggests that sufficient, appropriate mental health and social welfare support should be provided to those affected. Impact assessments of new policies on minority mental health should be embedded in all policy making. Funding: Wellcome Trust