Epidemiology of posttraumatic stress disorder:A prospective cohort study based on multiple nationwide Swedish registers of 4.6 million people

Background Experiencing exceptionally threatening or horrifying traumas can lead to posttraumatic stress disorder (PTSD). Increasing political unrest/war/natural disasters worldwide could cause more traumatic events and change the population burden of PTSD. Most PTSD research is based on surveys, prone to selection/recall biases with inconsistent results. The aim was therefore, to use register-based data to identify the occurrence of PTSD and contributing factors in the Swedish general population. Methods This register-based cohort study used survival analysis. Individuals born between 1960–1995, aged ≥15 years, registered and living in Sweden, not emigrating, anytime between 1990–2015, not receiving specialized care for PTSD before 2006 were included (N = 4,673,764), and followed from their 15th/16th birth date until first PTSD diagnosis between 2006–2016 or study endpoint (31-December-2016). PTSD cases (ICD-10: F43.1) were identified from the national patient register. Mean follow-up time was 18.8 years. Results Between 2006–2016, the incidence of specialized healthcare utilization for PTSD nearly doubled, and 0.7% of the study population received such care. The highest risk was observed for refugees [aHR 8.18; 95% CI:7.85–8.51] and for those with depressive disorder [aHR 4.51; 95% CI:3.95–5.14]. Higher PTSD risk was associated with female sex, older age, low education, single parenthood, low household income, urbanicity, and being born to a foreign-born parent. Conclusions PTSD is more common among refugee migrants, individuals with psychiatric disorders, and the socioeconomically disadvantaged. It is important that provision of services for PTSD are made available, particularly to these higher risk, and often hard-to-reach groups

Sickness absence around contact with outpatient mental health care services – differences between migrants and non-migrants:a Norwegian register study

Background: Mental disorders are a leading cause of sickness absence. Some groups of migrants are at higher risk of both mental disorder and sickness absence. Yet, research on sickness absence in relation to mental disorders among migrants is limited. This study investigates differences in sickness absence in the twelve-month period around contact with outpatient mental health services between non-migrants and various migrant groups with different length of stays. It also considers whether these differences are similar for men and women.Methods: Using linked Norwegian register data, we followed 146,785 individuals, aged 18–66 years, who had attended outpatient mental health services and who had, or had recently had, a stable workforce attachment. The number of days of sickness absence was calculated for the 12-month period surrounding contact with outpatient mental health services. We applied logistic regression and zero-truncated negative binomial regression to assess differences in any sickness absence and number of days of absence between non-migrants and migrants, including refugees and non-refugees. We included interaction terms between migrant category and sex.Results: Refugee men and other migrant men from countries outside the European Economic Area (EEA) had a higher probability of any sickness absence in the period surrounding contact with outpatient mental health services than their non-migrant counterparts. Women from EEA countries with stays of less than 15 years had a lower probability than non-migrant women. Additionally, refugees, both men and women, with 6–14 years in Norway had more days of absence while EEA migrants had fewer days than their non-migrant counterparts.Conclusions: Refugee men and other non-EEA migrant men appear to have higher sickness absence than non-migrant men around the time of contact with services. This finding does not apply to women. Several probable reasons for this are discussed, though further research is required to understand why. Targeted strategies to reduce sickness absence and support the return to work for refugees and other non-EEA migrant men are needed. Barriers to timely help-seeking should also be addressed.</p

Association of trauma, post-traumatic stress disorder and non-affective psychosis across the life course: a nationwide prospective cohort study

Background We aimed to examine the temporal relationships between traumatic events (TE), post-traumatic stress disorder (PTSD) and non-affective psychotic disorders (NAPD). Methods A prospective cohort study of 1 965 214 individuals born in Sweden between 1971 and 1990 examining the independent effects of interpersonal and non-interpersonal TE on incidence of PTSD and NAPD using data from linked register data (Psychiatry-Sweden). Mediation analyses tested the hypothesis that PTSD lies on a causal pathway between interpersonal trauma and NAPD. Results Increasing doses of interpersonal and non-interpersonal TE were independently associated with increased risk of NAPD [linear-trend incidence rate ratios (IRR)adjusted = 2.17 [95% confidence interval (CI) 2.02–2.33] and IRRadjusted = 1.27 (95% CI 1.23–1.31), respectively]. These attenuated to a relatively small degree in 5-year time-lagged models. A similar pattern of results was observed for PTSD [linear-trend IRRadjusted = 3.43 (95% CI 3.21–3.66) and IRRadjusted = 1.45 (95% CI 1.39–1.50)]. PTSD was associated with increased risk of NAPD [IRRadjusted = 8.06 (95% CI 7.23–8.99)], which was substantially attenuated in 5-year time-lagged analyses [IRRadjusted = 4.62 (95% CI 3.65–5.87)]. There was little evidence that PTSD diagnosis mediated the relationship between interpersonal TE and NAPD [IRRadjusted = 0.92 (percentile CI 0.80–1.07)]. Conclusion Despite the limitations to causal inference inherent in observational designs, the large effect-sizes observed between trauma, PTSD and NAPD in this study, consistent across sensitivity analyses, suggest that trauma may be a component cause of psychotic disorders. However, PTSD diagnosis might not be a good proxy for the likely complex psychological mechanisms mediating this association

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

Refugee status and the incidence of affective psychotic disorders and non-psychotic bipolar disorder: A register-based cohort study of 1.3m people in Sweden

BACKGROUND: Refugees are at increased risk of non-affective psychotic disorders, but it is unclear whether this extends to affective psychotic disorders [APD] or non-psychotic bipolar disorder [NPB]. METHODS: We conducted a nationwide cohort study in Sweden of all refugees, non-refugee migrants and the Swedish-born population, born 1 Jan 1984-31 Dec 2016. We followed participants from age 14 years until first ICD-10 diagnosis of APD or NPB. We fitted Cox proportional hazards models to estimate hazard ratios [HR] and 95 % confidence intervals [95%CI], adjusted for age, sex and family income. Models were additionally stratified by region-of-origin. RESULTS: We followed 1.3 million people for 15.1 million person-years, including 2428 new APD cases (rate: 16.0 per 100,000 person-years; 95%CI: 15.4-16.7) and 9425 NPB cases (rate: 63.8; 95%CI: 62.6-65.1). Rates of APD were higher in refugee (HRadjusted: 2.07; 95%CI: 1.55-2.78) and non-refugee migrants (HRadjusted: 1.40; 95%CI: 1.16-1.68), but lower for NPBs for refugee (HRadjusted: 0.24; 95%CI: 0.16-0.38) and non-refugee migrants (HRadjusted: 0.34; 95%CI: 0.28-0.41), compared with the Swedish-born. APD rates were elevated for both migrant groups from Asia and sub-Saharan Africa, but not other regions. Migrant groups from all regions-of-origin experienced lower rates of NPB. LIMITATIONS: Income may have been on the causal pathway making adjustment inappropriate. CONCLUSIONS: Refugees experience elevated rates of APD compared with Swedish-born and non-refugee migrants, but lower rates of NPB. This specificity of excess risk warrants clinical and public health investment in appropriate psychosis care for these vulnerable populations

The relationship between motherhood and use of mental health care services among married migrant and non-migrant women:a national register study

Background Giving birth to one's first child is a life changing event. Beyond the post-partum period, little is known about the association between becoming a mother and mental disorder among migrant women. This study investigates outpatient mental health (OPMH) service use, a proxy for mental disorder, among married migrant and non-migrant women who become mothers and those who do not. Methods Using Norwegian register data, we followed 90,195 married women, aged 18-40 years, with no children at baseline between 2008-2013 to see if becoming a mother was associated with OPMH service use. Data were analysed using discrete time analyses. Results We found an interaction between motherhood and migrant category. Married non-migrant mothers, both in the perinatal period and beyond, had lower odds of OPMH use than married non-mothers. There was no association between motherhood and OPMH service use for migrants. However, there was no significant interaction between motherhood and migrant category when we excluded women who had been in Norway less than five years. Among women aged 25-40 years, a stable labour market attachment was associated with lower odds of OPMH use for non-migrants but not migrants, regardless of motherhood status. Conclusions The perinatal period is not associated with increased odds of OPMH use and appears to be associated with lower odds for married non-migrant women. Selection effects and barriers to care may explain the lack of difference in OPMH service use that we found across motherhood status and labour market attachment for married migrant women. Married migrant women in general have a lower level of OPMH use than married non-migrants. Married migrant women with less than five years in Norway and those with no/weak labour market attachment may experience the greatest barriers to care. Further research to bridge the gap between need for, and use of, mental health care among migrant women is required.</p

Change in Work-Related Income Following the Uptake of Treatment for Mental Disorders Among Young Migrant and Non-migrant Women in Norway:A National Register Study

Background: Women, and migrant women in particular, are at increased risk of many common mental disorders, which may potentially impact their labor market participation and their work-related income. Previous research found that mental disorders are associated with several work-related outcomes such as loss of income, however, not much is known about how this varies with migrant background. This study investigated the change in work-related income following the uptake of outpatient mental healthcare (OPMH) treatment, a proxy for mental disorder, in young women with and without migrant background. Additionally, we looked at how the association varied by income level. Methods: Using data from four national registries, the study population consisted of women aged 23–40 years residing in Norway for at least three consecutive years between 2006 and 2013 (N = 640,527). By using a stratified linear regression with individual fixed effects, we investigated differences between majority women, descendants and eight migrant groups. Interaction analysis was conducted in order to examine differences in income loss following the uptake of OPMH treatment among women with and without migrant background. Results: Results showed that OPMH treatment was associated with a decrease in income for all groups. However, the negative effect was stronger among those with low income. Only migrant women from Western and EU Eastern Europe with a high income were not significantly affected following OPMH treatment. Conclusion: Experiencing a mental disorder during a critical age for establishment in the labor market can negatively affect not only income, but also future workforce participation, and increase dependency on social welfare services and other health outcomes, regardless of migrant background. Loss of income due to mental disorders can also affect future mental health, resulting in a vicious circle and contributing to more inequalities in the society

Migration and risk of intellectual disability with and without autism:A population-based cohort study

Objective To investigate whether parental migration, parental region of origin, timing of child's birth in relation to maternal migration and parental reason for migration are associated with intellectual disability (ID) with and without autism. Methods We used a register-based cohort of all individuals aged 0–17 years in Stockholm County during 2001–2011. General estimating equation logistic model and additionally sibling comparison were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). The models were adjusted for child's sex and birth year and parental age at child's birth, and additionally for migrant-specific variables in the analyses including only children with migrant parent(s). Results Within the eligible sample of 670,098 individuals, 3781 (0.6%) had ID with autism, and 5076 (0.8%) had ID without autism. Compared with children with Swedish-born parents, children with both parents born abroad had an increased risk of ID with autism (OR = 1.6, CI 1.5–1.8) and ID without autism (OR = 1.9, CI 1.7–2.0). Among these children with both parents born abroad, it was protective of ID with autism when the child's birth occurred before and later than four years after maternal migration, which was replicated in the sibling comparison. The associations with both conditions were more pronounced with parental origin in regions comprising low- and middle-income countries and with reasons other than work or study. Conclusions Parental migration is associated with ID regardless of co-occurrence of autism. Our results indicate an association between environmental factors during pregnancy related to migration and offspring ID with autism, although further confirmative studies are needed