Association between risk of dementia and very late-onset schizophrenia-like psychosis: a Swedish population-based cohort study

BACKGROUND

Although the incidence of psychotic disorders among older people is substantial, little is known about the association with subsequent dementia. We aimed to examine the rate of dementia diagnosis in individuals with very late-onset schizophrenia-like psychosis (VLOSLP) compared to those without VLOSLP.

METHODS

Using Swedish population register data, we established a cohort of 15 409 participants with VLOSLP matched by age and calendar period to 154 090 individuals without VLOSLP. Participants were born between 1920 and 1949 and followed from their date of first International Classification of Diseases [ICD], Revisions 8-10 (ICD-8/9/10) non-affective psychotic disorder diagnosis after age 60 years old (or the same date for matched participants) until the end of follow-up (30th December 2011), emigration, death, or first recorded ICD-8/9/10 dementia diagnosis.

RESULTS

We found a substantially higher rate of dementia in individuals with VLOSLP [hazard ratio (HR): 4.22, 95% confidence interval (95% CI) 4.05-4.41]. Median time-to-dementia-diagnosis was 75% shorter in those with VLOSLP (time ratio: 0.25, 95% CI 0.24-0.26). This association was strongest in the first year following VLOSLP diagnosis, and attenuated over time, although dementia rates remained higher in participants with VLOSLP for up to 20 years of follow-up. This association remained after accounting for potential misdiagnosis (2-year washout HR: 2.22, 95% CI 2.10-2.36), ascertainment bias (HR: 2.89, 95% CI 2.75-3.04), and differing mortality patterns between groups (subdistribution HR: 2.89, 95% CI 2.77-3.03).

CONCLUSIONS

Our findings demonstrate that individuals with VLOSLP represent a high-risk group for subsequent dementia. This may be due to early prodromal changes for some individuals, highlighting the importance of ongoing symptom monitoring in people with VLOSLP.

Risk of severe COVID-19 infection in individuals with severe mental disorders, substance use disorders, and common mental disorders

OBJECTIVE

To evaluate the risk of severe COVID-19 in individuals with severe mental disorders, substance use disorders, and common mental disorders in the total adult population of Region Stockholm (N = 1,516,270), and to explore possible underlying mechanisms to the increased risk.

METHODS

In this prospective cohort study, we examined the risk of hospitalization and treatment in an intensive care unit (ICU) with COVID-19, and death from COVID-19 for individuals with mental disorders. Associations were step by step adjusted for (1) sociodemographic/economic factors, (2) indicators of virus exposure, (3) somatic conditions, and (4) psychopharmacological treatment.

RESULTS

In model 1 (adjusted for age, sex and living in a care home for elderly people), people with a mental disorder had increased risks for inpatient care (HR = 1.5), ICU care (HR = 1.5), and mortality (HR = 1.4) from COVID-19. There was an increased risk of dying from COVID-19 in all subgroups of mental disorders, particularly in people with a severe mental disorder (HR = 1.9). Different covariates had different effects on the association depending on the outcome and on sex, age, or psychiatric diagnosis of the participants.

CONCLUSION

People with mental disorders have an increased risk of severe COVID-19, including mortality. The increased risk was partly explained by the examined covariates.

Migrant status and risk of compulsory admission at first diagnosis of psychotic disorder: a population-based cohort study in Sweden

BACKGROUND

Minority ethnic and migrant groups face an elevated risk of compulsory admission for mental illness. There are overlapping cultural, socio-demographic, and structural explanations for this risk that require further investigation.

METHODS

By linking Swedish national register data, we established a cohort of persons first diagnosed with a psychotic disorder between 2001 and 2016. We used multilevel mixed-effects logistic modelling to investigate variation in compulsory admission at first diagnosis of psychosis across migrant and Swedish-born groups with individual and neighbourhood-level covariates.

RESULTS

Our cohort included 12 000 individuals, with 1298 (10.8%) admitted compulsorily. In an unadjusted model, being a migrant [odds ratio (OR) 1.48; 95% confidence interval (CI) 1.26-1.73] or child of a migrant (OR 1.27; 95% CI 1.10-1.47) increased risk of compulsory admission. However after multivariable modelling, region-of-origin provided a better fit to the data than migrant status; excess risk of compulsory admission was elevated for individuals from sub-Saharan African (OR 1.94; 95% CI 1.51-2.49), Middle Eastern and North African (OR 1.46; 95% CI 1.17-1.81), non-Nordic European (OR 1.27; 95% CI 1.01-1.61), and mixed Swedish-Nordic backgrounds (OR 1.33; 95% CI 1.03-1.72). Risk of compulsory admission was greater in more densely populated neighbourhoods [OR per standard deviation (s.d.) increase in the exposure: 1.12, 95% CI 1.06-1.18], an effect that appeared to be driven by own-region migrant density (OR per s.d. increase in exposure: 1.12; 95% CI 1.02-1.24).

CONCLUSIONS

Inequalities in the risk of compulsory admission by migrant status, region-of-origin, urban living and own-region migrant density highlight discernible factors which raise barriers to equitable care and provide potential targets for intervention.

Early findings from periscope (Pan-European response to the impacts of COVID-19 and future pandemics and epidemics)

Abstract Body

The H2020/PERISCOPE project, including 32 partners from European universities & agencies, began 1st November 2020 and will last 36 months. The overarching objectives of PERISCOPE are to map and analyse the unintended impacts of the COVID-19 outbreak; develop solutions and guidance for policymakers and health authorities on how to mitigate the impact of the outbreak; enhance Europe’s preparedness for future similar events; and reflect on the future multi-level governance in the health as well as other domains affected by the outbreak. During this session we will report about early lessons learnt from the mapping and assessments of the impacts of the COVID-19 outbreak on mental health at national and subnational level in the EU with respect to individuals, communities and societies. Further, we will comment on their comparability. The aim is to explore differences between countries regarding the occurrence of mental ill health, and especially the impact on vulnerable groups, and how this is related to exposure to SARS-CoV-2, differences in policies over time, and effects on the economy. We will reflect on the short- and long-term consequences on mental health and health inequalities, report on the ongoing development of holistic policy guidelines for health authorities & other authorities, and from the analysis of multilevel governance, at local, regional and national level, memberstate – EU-level, and EU - global governance level. PERISCOPE will continue collecting data and updating a common data ”Atlas”, which would lead the consortium to engage in modelling and experiments to provide “continuous nowcasting” of the outbreak.

Disclosure

No significant relationships.

Association between preeclampsia and attention-deficit hyperactivity disorder: a population-based and sibling-matched cohort study

OBJECTIVE

To examine the association between preeclampsia and attention-deficit hyperactivity disorder (ADHD), using a large Swedish-based registry cohort.

METHODS

This study comprised 2 047 619 children, with 114 934 (5.6%) cases of ADHD. Preeclampsia was based on two alternate definitions: (i) preeclampsia (using ICD-9/ICD-10) and (ii) preeclampsia and small for gestational age (SGA) combined. ADHD was determined in one of two ways: (i) if a diagnosis of ADHD was present in the National Patient Register or (ii) if an individual was in receipt of ADHD medication in the Prescribed Drug Register. Multivariate Cox proportional hazards regression analysis allowed adjustment for several perinatal/sociodemographic factors. Sibling-matched analysis further controlled for shared genetic and familial confounding.

RESULTS

In the adjusted Cox model, preeclampsia was associated with an increase in likelihood of ADHD (HR: 1.15, 95% CI: 1.12, 1.19). The HR for preeclampsia and those born SGA was 1.43 (95% CI: 1.31, 1.55) in the adjusted model, compared to those unexposed to preeclampsia/SGA. The sibling-matched analysis did not materially change these associations (HR: 1.13, 95% CI: 1.05, 1.22) and 1.55 (95% CI: 1.28, 1.88).

CONCLUSIONS

Exposure to preeclampsia or preeclampsia/SGA was associated with ADHD, independent of genetic/familial factors shared by siblings. However, it is important to note that sibling-matched analysis can only adjust for factors that are constant between pregnancies; therefore, residual confounding cannot be ruled out. Further research is needed to explore modifiable risk factors and identify those most-at-risk babies following delivery.

Trends in psychiatric diagnoses, medications and psychological therapies in a large Swedish region: a population-based study

BACKGROUND

Health services utilization for mental health disorders is reported to increase sharply in many countries. The aim of this study was to report trends in all aspects of mental health care utilization in a total population sample.

METHODS

Repeated cross-sectional register study of the Stockholm Region (VAL) including both primary and secondary care. Trends in the proportion of adults in the total population of Stockholm Region with a recorded ICD-10 psychiatric diagnosis or psychological therapy during 2007-2017 as well as claims of psychiatric medication from 2011 were calculated.

RESULTS

The proportion of adults utilizing any mental health care increased from 13.2% in 2011 to 16.1% in 2017. In 2017, 49.3% were treated in primary care, 32.2% in secondary care and 18.5% were jointly managed. The increase was most pronounced in younger adults. Women were more likely to receive mental health care than men in all ages. Medication decreased from 71.0 to 67.7%, while psychological therapy increased from 33.1 to 37.6%. The use of psychiatric medication increased with age while psychological therapy decreased. All time trends were statistically significant (p < .0001).

CONCLUSION

Care for mental health disorders has been increasing mainly in primary care and was delivered to one in seven adult individuals in 2017. Interventions are needed to address the growing burden of mental health disorders while avoiding overtreatment.

Healthcare use prior to suicide in the Stockholm County population 2011-2016

Background

Suicide is a major public health problem. A detailed description of healthcare use prior to suicide can serve to improve prevention strategies. The aim of the study was to describe the patterns of primary, specialized outpatient, and inpatient healthcare use from two weeks and up to one year prior to suicide in Stockholm County.

Methods

The study population included all 15 year or older suicide victims who died in Stockholm County 2011-2016 (n = 1950) identified through National Cause of Death Registry. Data on number of visits and contacts with healthcare among suicide victims were obtained from VAL healthcare use registry in Stockholm County. Healthcare use was depicted from one year to up to two weeks prior to suicide death.

Results

Preliminary results showed that there were 65% and 57% of women and men, respectively, who had at least one contact with healthcare during the last two weeks before suicide death. Measured one year prior to suicide, there were 93% of women and 85% of men who had at least one contact with healthcare. Among those who had at least one contact with healthcare two weeks prior to suicide, there were 16% of women and 12% of men who were hospitalized, 55% of women and 47% of men who had a contact with specialized outpatient care, and 32% of women and 27% of men who had a contact with primary healthcare. The proportion of those who did not have any contact with healthcare during the six months prior to suicide decreased gradually with increasing age among men (23% at ages of 15-24 years old and 7% at ages of 65 and older). There were on average 7% of women in all age groups who did not have any contact with healthcare during the six months prior to suicide.

Conclusions

The majority of the suicide victims had a contact with healthcare during the last year prior to suicide death. The findings suggest that suicide prevention efforts may target improved tools for clinically-based risk assessment.

Key messages

The majority of the suicide victims had at least one contact with healthcare during the last year prior to suicide death. Those who did not have any contact with healthcare during six months prior to suicide were more likely to be young men.

Comparing cohort incidence of schizophrenia with that of bipolar disorder and affective psychosis in individuals born in Stockholm County 1955-1967

BACKGROUND

Perinatal factors are associated with increased risk for both schizophrenia and bipolar disorder. Improvements in obstetric and maternal healthcare and positive socioeconomic development in Sweden from the 1950s onwards could be expected to affect incidence estimates. However, commonly incidence rates are calculated during a specific year, i.e. time of diagnosis, which mirrors proximal precipitating risk factors. To examine whether incidence estimates are compatible with the hypothesis of an impact of perinatal exposures on the risk of the different disorders we here instead calculate incidence rates for consecutive birth cohorts born between 1955 and 1967. We hypothesized that schizophrenia incidence would be more affected compared to bipolar disorder and other affective psychoses since most perinatal risk factors are more pronounced in schizophrenia aetiology.

METHOD

Birth cohorts of individuals born in Sweden and resident in Stockholm (N = 2,16,322), were followed in The National Patient Register regarding incident inpatient episodes Incident cases/10,000 person-years and birth cohort were calculated. Linear regression was used to estimate change in incidence rate.

RESULTS

We found stable birth cohort-based incidence estimates for bipolar disorder and other affective psychoses, but a continuous reduction in incidence estimates for schizophrenia as well as other non-affective psychoses in subsequent birth cohorts from 1955 to 1967.

CONCLUSIONS

The consecutive birth cohort-based incidence estimates unveiled patterns that are compatible with the hypothesis of an impact of early life exposures decreasing over time, in the aetiology of schizophrenia, whereas this pattern is less apparent in affective psychoses..

Do eating disorders in parents predict eating disorders in children? Evidence from a Swedish cohort

OBJECTIVE

We investigated whether parental eating disorders (ED) predict ED in children, using a large multigeneration register-based sample.

METHOD

We used a subset of the Stockholm Youth Cohort born 1984-1995 and resident in Stockholm County in 2001-2007 (N = 286,232), The exposure was a diagnosed eating disorder in a parent; the outcome was any eating disorder diagnosis in their offspring, given by a specialist clinician, or inferred from an appointment at a specialist eating disorder clinic. A final study sample of 158,697 (55.4%) had data on these variables and confounding factors and contributed a total of 886,241 person years to the analysis.

RESULTS

We found good evidence in support of the hypothesis that ED in either parent are independently associated with ED in their female children (HR 1.97 (95% CI: 1.17-3.33), P = 0.01) and that ED in mothers are independently associated with ED in their female children (HR 2.35 (95% CI: 1.39-3.97) P = 0.001). Numbers were too low to permit separate analysis of ED in parents and their male children.

CONCLUSION

Eating disorders in parents were associated with ED in children. This study adds to our knowledge about the intergenerational transmission of ED, which will help identify high-risk groups and brings about the possibility of targeted prevention.

Testing Ødegaard's selective migration hypothesis: a longitudinal cohort study of risk factors for non-affective psychotic disorders among prospective emigrants

BACKGROUND

The selection hypothesis posits that the increased rates of psychosis observed among migrants are due to selective migration of people who are predisposed to develop the disorder. To test this hypothesis, we examined whether risk factors for psychosis are more prevalent among future emigrants.

METHOD

A cohort of 49,321 Swedish military conscripts was assessed at age 18 years on cannabis use, IQ, psychiatric diagnosis, social adjustment, history of trauma and urbanicity of place of upbringing. Through data linkage we examined whether these exposures predicted emigration out of Sweden. We also calculated the emigrants' hypothetical relative risk compared with non-emigrants for developing a non-affective psychotic disorder.

RESULTS

Low IQ [odds ratio (OR) 0.5, 95% confidence interval (95% CI) 0.3-0.9] and 'poor social adjustment' (OR 0.4, 95% CI 0.2-0.8) were significantly less prevalent among prospective emigrants, whereas a history of urban upbringing (OR 2.3, 95% CI 1.4-3.7) was significantly more common. Apart from a non-significant increase in cannabis use among emigrants (OR 1.6, 95% CI 0.8-3.1), there were no major group differences in any other risk factors. Compared to non-emigrants, hypothetical relative risks for developing non-affective psychotic disorder were 0.7 (95% CI 0.4-1.2) and 0.8 (95% CI 0.7-1.0), respectively, for emigrants narrowly and broadly defined.

CONCLUSIONS

This study adds to an increasing body of evidence opposing the selection hypothesis.

Influence of maternal infections on neonatal acute phase proteins and their interaction in the development of non-affective psychosis

Although primary infections with Toxoplasma gondii or herpes viruses during pregnancy are established teratogens, chronic maternal infections with these pathogens are considered far less serious. However, such chronic infections have been associated with neuropsychiatric disorders in the offspring. The risks of non-affective psychoses, including schizophrenia, in offspring associated with these exposures during pregnancy have not been completely defined. We used data from neonatal dried blood samples from 199 cases of non-affective psychosis and 525 matched controls (born 1975-1985). We measure immunoglobulin G antibodies directed at T. gondii, cytomegalovirus and herpes simplex virus type-1 and -2, as well as levels of nine acute phase proteins (APPs). We assessed the interaction between maternal antibodies and neonatal APP in terms of risk of non-affective psychosis. Among controls, maternal exposure to T. gondii or cytomegalovirus, but not to the other herpes viruses, was associated with significantly higher levels of neonatal APPs. Among cases, none of the maternal exposures were associated with any significant change in APPs. We observed increased RR for non-affective psychosis associated with maternal infection with T. gondii (odds ratio 2.1, 95% confidence interval 1.1-4.0) or cytomegalovirus (1.7, 0.9-3.3) only among neonates with low APP levels. These findings suggest that chronic maternal infection with T. gondii or cytomegalovirus affect neonatal markers of innate immunity. Deficient fetal immune responses in combination with maternal chronic infections may contribute to subsequent risk for psychosis. A greater understanding of the maternal-fetal immunological interplay may ultimately lead to preventive strategies toward neuropsychiatric disorders.

Prognosis of schizophrenia in persons with and without a history of cannabis use

BACKGROUND

The aim of the study was to determinate whether schizophrenia patients with a history of cannabis use have a different prognosis, with regards to readmission and hospital duration, compared with those without a history of cannabis use.

METHOD

The present investigation was a cohort study of 50,087 Swedish men with data on cannabis use at the ages of 18-20 years. A total of 357 cases of schizophrenia were identified from in-patient care and followed up from 1973 to 2007.

RESULTS

Schizophrenia patients with a history of cannabis use had a higher median duration of first hospital episode (59 days v. 30 days). Patients with a history of cannabis use had a higher median rate of readmission (10 times v. four times). Also, total number of hospital days was higher in patients with a history of cannabis use compared with those without (547 days v. 184 days). Patients with a history of cannabis use had an increased odds of having more than 20 hospital readmissions compared with non-users [3.1, 95% confidence interval (CI) 1.3-7.3] as well as an increased odds of hospital admission lasting more than 2 years (2.4, 95% CI 1.1-7.4) after controlling for diagnosis of personality disorders, family socio-economic position, IQ score, civil status, place of residence, risky use of alcohol and use of other drugs. Patients with a history of cannabis use were less likely to have paranoid schizophrenia compared with never users (8% v. 17%) in the first admission.

CONCLUSIONS

Schizophrenia patients with a history of cannabis use had a significantly higher burden of lifetime in-patient care than non-cannabis users. Not only does cannabis increase the risk of schizophrenia, but also our findings indicate that the course and prognosis of schizophrenia may be more severe than schizophrenia cases in general.

School performance and the risk of suicide attempts in young adults: a longitudinal population-based study

BACKGROUND

Poor school performance is strongly associated with attempted suicide, but the mechanisms underlying this association are uncertain. We examined this relationship and the extent to which it is explained by (i) adult health behaviours and (ii) social conditions. Furthermore, we examined the potential modifying role of previous suicidal thoughts in the relationship.

METHOD

We conducted a longitudinal cohort study of 6146 individuals aged 18-33 years, recruited in 2002 and 2006 in Stockholm and resurveyed in 2007 and 2010 respectively. We estimated the risk of reported lifetime suicide attempts at follow-up among individuals without a history of suicide attempts at baseline and in relation to compulsory school-leaving grades, controlling for possible confounders and mediators.

RESULTS

There were 91 cases of self-reported suicide attempts during the follow-up (5-year incidence of 1.5%). ORs ranged from 3.35 [95% confidence interval (CI) 1.88-5.96] for those in the lowest grade quartile to 2.60 (95% CI 1.48-4.57) and 1.76 (95% CI 0.99-3.13) for those in the second and third quartiles respectively. The relationship between school performance and risk of suicide attempts did not differ by sex. Adult health behaviours and social conditions marginally attenuated, but did not explain, the relationship. The gradient varied with baseline history of suicidal thoughts, and was found only among individuals without such a history.

CONCLUSIONS

Poor school performance was found to predict suicide attempts among young adults without a history of suicidal thoughts. Adult health behaviours and social conditions did not explain this relationship. Instead, other factors linked with poor school performance, such as poor coping ability, may increase the risk of suicide attempts.

Severe bereavement stress during the prenatal and childhood periods and risk of psychosis in later life: population based cohort study

OBJECTIVE

To examine the risk of psychosis associated with severe bereavement stress during the antenatal and postnatal period, between conception to adolescence, and with different causes of death.

DESIGN

Population based cohort study.

SETTING

Swedish national registers including births between 1973 and 1985 and followed-up to 2006.

PARTICIPANTS

In a cohort of 1,045,336 Swedish births (1973-85), offspring born to mothers exposed to severe maternal bereavement stress six months before conception or during pregnancy, or exposed to loss of a close family member subsequently from birth to 13 years of age were followed until 2006. Admissions were identified by linkage to national patient registers.

MAIN OUTCOME MEASURES

Crude and adjusted odds ratios for all psychosis, non-affective psychosis, and affective psychosis.

RESULTS

Maternal bereavement stress occurring preconception or during the prenatal period was not associated with a significant excess risk of psychosis in offspring (adjusted odds ratio, preconception 1.24, 95% confidence interval 0.96 to 1.62; first trimester 0.95, 0.58 to 1.56; second trimester 0.79, 0.46 to 1.33; third trimester 1.14, 0.78 to 1.66). Risks increased modestly after exposure to the loss of a close family member from birth to adolescence for all psychoses (adjusted odds ratio 1.17, 1.04 to 1.32). The pattern of risk was generally similar for non-affective and affective psychosis. Thus estimates were higher after death in the nuclear compared with extended family but remained non-significant for prenatal exposure; the earlier the exposure to death in the nuclear family occurred in childhood (all psychoses: adjusted odds ratio, birth to 2.9 years 1.84, 1.41 to 2.41; 3-6.9 years 1.47, 1.16 to 1.85; 7-12.9 years 1.32, 1.10 to 1.58) and after suicide. Following suicide, risks were especially higher for affective psychosis (birth to 2.9 years 3.33, 2.00 to 5.56; 6.9 years 1.84, 1.04 to 3.25; 7-12.9 years 2.68, 1.84 to 3.92). Adjustment for key confounders attenuated but did not explain associations with risk.

CONCLUSIONS

Postnatal but not prenatal bereavement stress in mothers is associated with an increased risk of psychosis in offspring. Risks are especially high for affective psychosis after suicide in the nuclear family, an effect that is not explained by family psychiatric history. Future studies are needed to understand possible sources of risk and resilience so that structures can be put in place to support vulnerable children and their families.

Individual- and area-level influence on suicide risk: a multilevel longitudinal study of Swedish schoolchildren

BACKGROUND

Characteristics related to the areas where people live have been associated with suicide risk, although these might reflect aggregation into these communities of individuals with mental health or social problems. No studies have examined whether area characteristics during childhood are associated with subsequent suicide, or whether risk associated with individual characteristics varies according to childhood neighbourhood context.

METHOD

We conducted a longitudinal study of 204,323 individuals born in Sweden in 1972 and 1977 with childhood data linked to suicide (n = 314; 0.15%) up to age 26-31 years. Multilevel modelling was used to examine: (i) whether school-, municipality- or county-level characteristics during childhood are associated with later suicide, independently of individual effects, and (ii) whether associations between individual characteristics and suicide vary according to school context (reflecting both peer group and neighbourhood effects).

RESULTS

Associations between suicide and most contextual measures, except for school-level gender composition, were explained by individual characteristics. There was some evidence of cross-level effects of individual- and school-level markers of ethnicity and deprivation on suicide risk, with qualitative interaction patterns. For example, having foreign-born parents increased the risk for individuals raised in areas where they were in a relative minority, but protected against suicide in areas where larger proportions of the population had foreign-born parents.

CONCLUSIONS

Characteristics that define individuals as being different from most people in their local environment as they grow up may increase suicide risk. If robustly replicated, these findings have potentially important implications for understanding the aetiology of suicide and informing social policy.

Hearing and speech impairment at age 4 and risk of later non-affective psychosis

BACKGROUND

Schizophrenia often becomes manifest in late adolescence and young adulthood but deviations in physical and behavioural development may already be present in childhood. We investigated the relationship between hearing impairment (measured with audiometry) and speech impairment (broadly defined) at age 4 years and adult risk of non-affective psychosis.

METHOD

We performed a population-based, case–control study in Sweden with 105 cases of schizophrenia or other non-affective psychoses and 213 controls matched for sex, date and place of birth. Information on hearing and speech impairment at age 4, along with potential confounding factors, was retrieved from Well Baby Clinic (WBC) records.

RESULTS

Hearing impairment [odds ratio (OR) 6.0, 95% confidence interval (CI) 1.6–23.2] and speech impairment (OR 2.6, 95% CI 1.4–4.9) at age 4 were associated with an increased risk of non-affective psychotic illness. These associations were mutually independent and not explained by parental psychiatric history, occupational class or obstetric complications.

CONCLUSIONS

These results support the hypothesis that psychosis has a developmental aspect with presentation of antecedent markers early in childhood, long before the disease becomes manifest. Our findings add to the growing evidence that early hearing impairment and speech impairment are risk indicators for later non-affective psychosis and possibly represent aetiological clues and potentially modifiable risk factors. Notably, speech impairment and language impairment are both detectable with inexpensive, easily accessible screening.

Neonatal levels of acute phase proteins and later risk of non-affective psychosis

Mounting evidence suggests that immune disturbances in early life may be implicated in the etiology of non-affective psychoses. Our aim was to assess the levels of neonatal acute phase proteins (APPs), central to innate immune function as well as central nervous system development, in neonatal dried blood spots and their association with later risk of non-affective psychoses. This case-control study included 196 individuals with a verified register-based diagnosis of non-affective psychosis and 502 controls matched on age, sex and hospital of birth. Concentrations of nine different APPs were measured in eluates from dried blood spots using a bead-based multiplex assay. Odds ratios (OR) for non-affective psychoses were calculated for log(2)-transformed (continuous) as well as tertiles of APP concentrations. In continuous analysis, higher concentrations of two APPs, tissue plasminogen activator (tPA; OR: 0.90, 95% confidence interval (CI): 0.85-0.96) and serum amyloid P (SAP; OR: 0.88, 95% CI: 0.78-0.99) were protective in terms of risk of non-affective psychosis. These relationships were not affected by the addition of covariates relevant to maternal health, pregnancy and delivery to the model. Tertile analysis confirmed a protective relationship for higher levels of tPA and SAP, as well as for procalcitonin (highest tertile OR: 0.54, 95% CI:0.32-0.91). Our results suggest that persons who develop non-affective psychoses have lower levels of certain APPs at the time of birth. These differences may render individuals more susceptible to infectious diseases or cause deficiencies in pathways critical for neurodevelopment.

Cannabis, schizophrenia and other non-affective psychoses: 35 years of follow-up of a population-based cohort

BACKGROUND

There is now strong evidence that cannabis use increases the risk of psychoses including schizophrenia, but the relationship between cannabis and different psychotic disorders, as well as the mechanisms, are poorly known. We aimed to assess types of psychotic outcomes after use of cannabis in adolescence and variation in risk over time.

METHOD

A cohort of 50 087 military conscripts with data on cannabis use in late adolescence was followed up during 35 years with regard to in-patient care for psychotic diagnoses.

RESULTS

Odds ratios for psychotic outcomes among frequent cannabis users compared with non-users were 3.7 [95% confidence interval (CI) 2.3-5.8] for schizophrenia, 2.2 (95% CI 1.0-4.7) for brief psychosis and 2.0 (95% CI 0.8-4.7) for other non-affective psychoses. Risk of schizophrenia declined over the decades in moderate users but much less so in frequent users. The presence of a brief psychosis did not increase risk of later schizophrenia more in cannabis users compared with non-users.

CONCLUSIONS

Our results confirm an increased risk of schizophrenia in a long-term perspective, although the risk declined over time in moderate users.

FC08-06 - Distress or depression? does socioeconomic position matter?

Introduction

It is not well known whether the association between common mental disorders and low socioeconomic status vary with symptom severity, type of socioeconomic indicator or gender.

Objectives

To study the association between socioeconomic status and risk for different severity levels of psychological distress as well as depression.

Methods

A population-based survey was conducted among a random sample of Stockholm County residents aged 18–84 years in 2002, and respondents were reassessed via a follow-up questionnaire in 2007. Participants in both surveys (n = 23 794) were categorized according to socioeconomic status at baseline and followed up for onset of psychological distress (according to the twelve-item general health questionnaire) and depression (according to health data registers).

Results

Occupational class had little impact on risk for distress regardless of severity or gender, but was strongly associated with onset of depression - albeit only in men (ORs being 3.0 [95% CI 1.5–5.9] in men and 1.1 [95% CI (0.7–1.7]) in women, comparing unskilled manual workers with higher non-manual workers). Income was associated with risk for onset of all outcomes and the association grew stronger with symptom severity. High household income was particularly protective of depression in women. Education was unrelated to either outcome in men and women overall.

Conclusions

While psychological distress appears to occur at a similar rate regardless of socioeconomic position, risks for severe distress and especially clinically overt depression are markedly linked with occupational class in men and with family income in women. The socioeconomic gradient in common mental disorders increases with symptom severity.

Social adversity contributes to high morbidity in psychoses in immigrants--a national cohort study in two generations of Swedish residents

BACKGROUND

Recent reports have indicated that immigrants have an elevated risk of schizophrenia as well as an increasing tendency for social exclusion. The aim of this study was to compare rates of schizophrenia and other psychoses in immigrants and their children of different ethnic groups with the majority population in Sweden in relation to social adversity.

METHOD

The study population consists of a national cohort of 1.47 million adults (born 1929-1965) and 1.16 million children and youth (born 1968-1979) in family households from the national census of 1985. Multivariate Cox regression analyses was used to study hospital discharge data during 1991-2000 in relation to socio-economic household indicators from 1985 and 1990 (single adult household, adults having received social welfare, parental unemployment, urban residency, housing and socio-economic status).

RESULTS

First as well as second generation immigrants had higher age and sex adjusted risk ratios for schizophrenia as well as for other psychoses (RRs 1.4-3.1 and 1.0-2.0 respectively) compared with the Swedish majority population. These risk ratios decreased considerably after adjusting for socio-economic indicators, for all groups, but particularly for the non-European immigrants. However, an elevated risk still remained in the Finnish and Eastern and Southern European study groups.

CONCLUSIONS

A higher risk of schizophrenia and psychoses was found in two generations of immigrants of diverse ethnicity. The results indicate that social adversity contributes to the higher risk.

Obstetric complications and risk of schizophrenia. Effect of gender, age at diagnosis and maternal history of psychosis

BACKGROUND

Obstetric complications have been studied frequently as possible risk factors for schizophrenia.

AIMS

To test the hypotheses that individual obstetric complications are most strongly associated with an increased risk of schizophrenia in males, in patients with an early age at first diagnosis and in subjects with a maternal history of psychosis.

METHOD

Cases of schizophrenia diagnosed between January 1971 and June 1994 were identified in the Stockholm County In-Patient Register. Controls were matched on age, gender, hospital of birth and parish of birth. Obstetric data were recorded blind to case-control status for 524 cases and 1043 controls.

RESULTS

This study did not find any large or consistent effect of gender, age at diagnosis or maternal history of psychosis on the risk of schizophrenia associated with individual complications.

CONCLUSIONS

Future studies should examine these effects using a much larger sample that includes patients with schizophrenia and control subjects whose genetic risk of schizophrenia has been assessed accurately.

Signs of asphyxia at birth and risk of schizophrenia. Population-based case-control study

BACKGROUND

Previous research has found an association between obstetric complications and schizophrenia, but in many studies the sample size was limited, and no assessment of specific exposures was possible.

AIMS

To assess the role of different complications, and in particular to distinguish between disordered foetal development and hypoxia at birth.

METHOD

From the Stockholm County In-Patient Register and community registers, we identified 524 cases of schizophrenia and 1043 controls, matched for age, gender, hospital and parish of birth. Data on obstetric complications were obtained from birth records.

RESULTS

There was a strong association between signs of asphyxia at birth and schizophrenia (OR 4.4; 95% C11.9-10.3) after adjustment for other obstetric complications, maternal history of psychotic illness and social class.

CONCLUSIONS

Signs of asphyxia at birth are associated with an increased risk of schizophrenia in adults.

Neonatal hyperbilirubinaemia--a vulnerability factor for mental disorder?

OBJECTIVE

Various studies have shown an association between obstetric complications and psychiatric illness. There is a lack of specific aetiological explanations. A possible mechanism contributing to cerebral vulnerability is neonatal hyperbilirubinaemia (NHB).

METHOD

A total of 509 children with NHB (bilirubin > 15 mg %) were compared with the same number of controls (matched for gender, place of residence, and date and place of birth) with respect to in-patient psychiatric care during 1971-1993.

RESULTS

A significantly greater number of individuals in the NHB group received in-patient psychiatric care than in the control group (OR, 2.5; 95% CI, 1.1-5.5). After exclusion of infants with associated obstetric risk factors, the significantly increased risk for in-patient psychiatric care still remained among the children with NHB (OR, 13.4; 95% CI, 1.6-110.1).

CONCLUSION

NHB could be a factor underlying subsequent development of mental ill-health, but larger samples are needed to obtain a more reliable assessment.

Obstetric complications and the risk of schizophrenia: a longitudinal study of a national birth cohort

BACKGROUND

Numerous epidemiological studies found an increased risk of schizophrenia among persons exposed to various obstetric complications. The underlying mechanisms are unknown.

OBJECTIVE

To study specific risk factors, as well as sets of risk factors, representing 3 different etiologic mechanisms: (1) malnutrition during fetal life; (2) extreme prematurity; and (3) hypoxia or ischemia.

METHODS

In this longitudinal cohort study, information in the National Birth Register was linked to the National Inpatient Register. We followed up 507516 children born between 1973 and 1977 with regard to a diagnosis of schizophrenia between 1987 and 1995 (238 cases). By record linkage, we also had access to data on psychiatric illness in the mother. Occurrence of schizophrenia was measured by the Mantel-Haenszel test and logistic regression.

RESULTS

A number of specific risk factors were associated with an increased risk of schizophrenia. The relative risk (95% confidence interval) for preeclampsia was 2.5 (1.4-4.5); vacuum extraction, 1.7 (1.1-2.6); and malformations, 2.4 (1.2-5.1). In logistic regression models, we found that indicators of all 3 etiologic mechanisms were associated with increased point estimates of schizophrenia, although at lower risk levels. Preeclampsia, an indicator of fetal malnutrition, was the only risk factor with statistically significant increased risk after control for all potentially confounding factors.

CONCLUSION

This study supports the theory of an association between obstetric complications and schizophrenia. Although preeclampsia was the strongest individual risk factor, there was evidence of increased risk associated with all 3 etiologic mechanisms.