Effect of social class at birth on risk and presentation of schizophrenia: case-control study

Low income and schizophrenia risk: a narrative review

Despite decades of research, the precise etiology of schizophrenia is not fully understood. Ample evidence indicates that the disorder derives from a complex interplay of genetic and environmental factors during vulnerable stages of brain maturation. Among the plethora of risk factors investigated, stress, pre- and perinatal insults, and cannabis use have been repeatedly highlighted as crucial environmental risk factors for schizophrenia. Compelling findings from population-based longitudinal studies suggest low income as an additional risk factor for future schizophrenia diagnosis, but underlying mechanisms remain unclear. In this narrative review, we 1) summarize the literature in support of a relationship between low (parental) income and schizophrenia risk, and 2) explore the mediating role of chronic stress, pre- and perinatal factors, and cannabis use as established risk factors for schizophrenia. Our review describes how low income facilitates the occurrence and severity of these established risk factors and thus contributes to schizophrenia liability. The broadest influence of low income was identified for stress, as low income was found to be associated with exposure to a multitude of severe psychological and physiological stressors. This narrative review adds to the growing literature reporting a close relationship between income and mental health.

Dysfunctional family functioning in high socioeconomic status families as a risk factor for the development of psychiatric disorders in adoptees: the Finnish Adoptive Family Study of Schizophrenia

PURPOSE

Earlier findings indicate that socioeconomic status (SES) of family associates with family functioning. This study examined the impacts of family functioning and genetic risk for schizophrenia on psychiatric morbidity of adoptees in families of high SES (HSES) and low SES (LSES).

METHODS

The study population is a subgroup of the Finnish Adoptive Family Study of Schizophrenia. Of the adoptees, 152 had high genetic risk for schizophrenia spectrum disorders (HR) and 151 adoptees had low risk (LR). Of the adoptees, 185 (HR = 94, LR = 91) were raised in high-SES (HSES) families and 118 (HR = 58, LR = 60) in low-SES (LSES) families. The family SES was determined by the occupational status of the main provider of the family. The functioning of adoptive families was assessed based on Global Family Ratings (GFRs) and psychiatric disorders on DSM-III-R criteria.

RESULTS

In the HSES families, the psychiatric morbidity of the adoptees was emphasized by HR (OR = 4.28, CI 2.14-8.56) and dysfunctional family processes (OR = 6.44, CI 2.75-15.04). In the LSES families, the adoptees´ psychiatric morbidity was almost significantly increased by HR (OR = 2.10, CI 0.99-4.45), but not by dysfunctional family processes (OR = 1.33, CI 0.53-3.34).

CONCLUSIONS

This study showed that in HSES families, dysfunctional family processes and HR for schizophrenia increased the likelihoods for the development of psychiatric disorders in adoptees. The results can be utilized in identifying risk factors in the development of psychiatric disorders and focusing preventative strategies on risk groups with acknowledging the importance of family functioning.

Altered gut microbiota associated with symptom severity in schizophrenia

BACKGROUND

The gut microbiome and microbiome-gut-brain (MGB) axis have been receiving increasing attention for their role in the regulation of mental behavior and possible biological basis of psychiatric disorders. With the advance of next-generation sequencing technology, characterization of the gut microbiota in schizophrenia (SZ) patients can provide rich clues for the diagnosis and prevention of SZ.

METHODS

In this study, we compared the differences in the fecal microbiota between 82 SZ patients and 80 demographically matched normal controls (NCs) by 16S rRNA sequencing and analyzed the correlations between altered gut microbiota and symptom severity.

RESULTS

The alpha diversity showed no significant differences between the NC and SZ groups, but the beta diversity revealed significant community-level separation in microbiome composition between the two groups (pseudo-F =3.337, p < 0.001, uncorrected). At the phylum level, relatively more Actinobacteria and less Firmicutes (p < 0.05, FDR corrected) were found in the SZ group. At the genus level, the relative abundances of Collinsella, Lactobacillus, Succinivibrio, Mogibacterium, Corynebacterium, undefined Ruminococcus and undefined Eubacterium were significantly increased, whereas the abundances of Adlercreutzia, Anaerostipes, Ruminococcus and Faecalibacterium were decreased in the SZ group compared to the NC group (p < 0.05, FDR corrected). We performed PICRUSt analysis and found that several metabolic pathways differed significantly between the two groups, including the Polyketide sugar unit biosynthesis, Valine, Leucine and Isoleucine biosynthesis, Pantothenate and CoA biosynthesis, C5-Branched dibasic acid metabolism, Phenylpropanoid biosynthesis, Ascorbate and aldarate metabolism, Nucleotide metabolism and Propanoate metabolism pathways (p < 0.05, FDR corrected). Among the SZ group, the abundance of Succinivibrio was positively correlated with the total Positive and Negative Syndrome Scale (PANSS) scores (r = 0.24, p < 0.05, uncorrected) as well as the general PANSS scores (r = 0.22, p < 0.05, uncorrected); Corynebacterium was negatively related to the negative scores of PANSS (r = 0.22, p < 0.05, uncorrected).

CONCLUSIONS

Our findings provided evidence of altered gut microbial composition in SZ group. In addition, we found that Succinvibrio and Corynebacterium were associated with the severity of symptoms for the first time, which may provide some new biomarkers for the diagnosis of SZ.

Social class and type of schizophrenia

Objective

Current and past research strongly indicates a high prevalence of schizophrenia in the lower class in the USA and other stratified societies. To date, no study has tested for a connection between type of schizophrenia and socioeconomic status (SES). We tested for an interrelationship between schizophrenic subtype, SES and race.

Methods

Positive and negative symptom scales were used to evaluate 436 schizophrenic patients at a state hospital in the USA. All patients were also diagnosed by DSM standards. Social class of origin was assessed by the Occupational Classification Distributions of the U.S. Bureau of the Census. Multivariate analysis was conducted with the likelihood ratio chi-square.

Results

We uncovered a distinct propensity for deficit schizophrenia to be elevated among the poor. The finding presents as a pure SES effect since the likelihood of deficit schizophrenia does not vary by race when social class is held constant.

Conclusion

The finding is potentially an important new insight into the epidemiology of schizophrenia. It offers a better understanding for poor outcome among lower class patients in stratified societies such as the United States. It is also consistent with longitudinal research by European investigators.

Association Between Parental Income During Childhood and Risk of Schizophrenia Later in Life

IMPORTANCE

Evidence linking parental socioeconomic position and offspring's schizophrenia risk has been inconsistent, and how risk is associated with parental socioeconomic mobility has not been investigated.

OBJECTIVE

To elucidate the association between parental income level and income mobility during childhood and subsequent schizophrenia risk.

DESIGN, SETTING, AND PARTICIPANTS

National cohort study of all persons born in Denmark from January 1, 1980, to December 31, 2000, who were followed up from their 15th birthday until schizophrenia diagnosis, emigration, death, or December 31, 2016, whichever came first. Data analyses were from March 2018 to June 2019.

EXPOSURE

Parental income, measured at birth year and at child ages 5, 10, and 15 years.

MAIN OUTCOMES AND MEASURES

Hazard ratios (HRs) for schizophrenia were estimated using Cox proportional hazard regression. Cumulative incidence values (absolute risks) were also calculated.

RESULTS

The cohort included 1 051 033 participants, of whom 51.3% were male. Of the cohort members, 7544 (4124 [54.7%] male) were diagnosed with schizophrenia during 11.6 million person-years of follow-up. There was an inverse association between parental income level and subsequent schizophrenia risk, with children from lower income families having especially elevated risk. Estimates were attenuated, but risk gradients remained after adjustment for urbanization, parental mental disorders, parental educational levels, and number of changes in child-parent separation status. A dose-response association was observed with increasing amount of time spent in low-income conditions being linked with higher schizophrenia risk. Regardless of parental income level at birth, upward income mobility was associated with lower schizophrenia risk compared with downward mobility. For example, children who were born and remained in the lowest income quintile at age 15 years had a 4.12 (95% CI, 3.71-4.58) elevated risk compared with the reference group, those who were born in and remained in the most affluent quintile, but even a rise from the lowest income quintile at birth to second lowest at age 15 years appeared to lessen the risk elevation (HR, 2.80; 95% CI, 2.46-3.17). On the contrary, for those born in the most affluent quintile, downward income mobility between birth and age 15 years was associated with increased risks of developing schizophrenia.

CONCLUSIONS AND RELEVANCE

This study's findings suggest that parental income level and income mobility during childhood may be linked with schizophrenia risk. Although both causation and selection mechanisms could be involved, enabling upward income mobility could influence schizophrenia incidence at the population level.

Psychopathology, cognition and outcome in Dutch and immigrant first-episode psychosis patients

AIM

The primary aim was to examine differences in baseline symptom expression, neurocognition, social cognition and psychosocial functioning between Dutch, first-generation immigrants and second-generation immigrants with a first-episode psychosis (FEP). The secondary aim was to examine functional and symptomatic change and between-group differences at 12-months follow-up. Associations between migration, baseline characteristics and outcome were explored.

METHODS

Forty-six Dutch, 56 second-generation- and 60 first-generation immigrant patients completed baseline measures for 6 symptom dimensions (positive symptoms, negative symptoms, neurocognitive functioning, social cognitive functioning, excitement and emotional distress) and 5 domains of psychosocial functioning (general functioning, work and study, relationships, self-care and disturbing behaviour). Functioning and psychotic symptoms were assessed at baseline and 12-months follow-up. ANCOVA and t tests were used to assess between-group differences. General linear models were used to explore within-group differences. Backward-regression was used to explore predictors of outcome.

RESULTS

Levels of positive symptoms, excitement and emotional distress did not differ between groups at baseline or follow-up. Dutch patients had lower levels of negative symptoms than both immigrant groups at follow-up. On neurocognition and social cognition, Dutch performed better than second-generation immigrants, who in turn performed better than first-generation immigrants. Psychosocial functioning across all domains at baseline and at 12-months follow-up was similar across groups. Baseline levels of general psychosocial functioning and income were the strongest predictors of outcome at follow-up.

CONCLUSIONS

Psychosocial functioning and symptom profiles are comparable between Dutch, first-generation immigrant and second-generation immigrant FEP patients, excluding neurocognitive and social cognitive deficits. A range of baseline characteristics predicted outcome.

Parental characteristics and the risk of schizophrenia in a Chinese population: a case-control study

BACKGROUND

Genetic studies have provided convergent results indicating that schizophrenia is a polygenic disorder with a heritability estimate of ∼60-80%. The propensity for schizophrenia is ∼10 times higher in individuals with first-degree relatives with schizophrenia when compared to the general population.

AIM

To identify associations between parental characteristics and the risk of schizophrenia in a Chinese population.

METHODS

Participants with a diagnosis of schizophrenia were recruited along with healthy controls (HCs) matched for age and gender from Weifang, China. Logistic regression models and generalized linear models were used to explore the associations between parental characteristics with the risk and age at onset of schizophrenia. In total, 414 cases and 639 HCs were recruited for the study.

RESULTS

We observed an inverse association between levels of paternal and maternal education and risk of schizophrenia after controlling for potential confounders (Paternal: OR = 1.525, 95% CI: 1.080-2.153, p = .017; Maternal: OR = 1.984, 95% CI: 1.346-2.924, p = .001). Younger paternal and maternal childbearing age were associated with a higher risk of diagnosis of schizophrenia. We furtherly observed that individuals with earlier age at onset of schizophrenia had fewer siblings (p = .007) and had higher rates of parental marital disharmony (p = .033).

CONCLUSION

Our results indicate that parental years of education and age of childbearing are associated with an increased risk of schizophrenia in a Chinese population. Age of onset of schizophrenia was positively associated with a greater number of siblings and negatively associated with parental marital disharmony.

Non-Genetic Factors in Schizophrenia

PURPOSE OF REVIEW

We review recent developments on risk factors in schizophrenia.

RECENT FINDINGS

The way we think about schizophrenia today is profoundly different from the way this illness was seen in the twentieth century. We now know that the etiology of schizophrenia is multifactorial and reflects an interaction between genetic vulnerability and environmental contributors. Environmental risk factors such as pregnancy and birth complications, childhood trauma, migration, social isolation, urbanicity, and substance abuse, alone and in combination, acting at a number of levels over time, influence the individual's likelihood to develop the disorder. Environmental risk factors together with the identification of a polygenic risk score for schizophrenia, research on gene-environment interaction and environment-environment interaction have hugely increased our knowledge of the disorder.

Poverty, social inequality and mental health

The World Health Organization has described poverty as the greatest cause of suffering on earth. This article considers the direct and indirect effects of relative poverty on the development of emotional, behavioural and psychiatric problems, in the context of the growing inequality between rich and poor. The problems of children in particular are reviewed. Targets to reduce inequality have been set both nationally and internationally.

Curiosity killed the cat: no evidence of an association between cat ownership and psychotic symptoms at ages 13 and 18 years in a UK general population cohort

BACKGROUND

Congenital or early life infection with Toxoplasma gondii has been implicated in schizophrenia aetiology. Childhood cat ownership has been hypothesized as an intermediary marker of T. gondii infection and, by proxy, as a risk factor for later psychosis. Evidence supporting this hypothesis is, however, limited.

METHOD

We used birth cohort data from the Avon Longitudinal Study of Parents and Children (ALSPAC) to investigate whether cat ownership in pregnancy and childhood (ages 4 and 10 years) was associated with psychotic experiences (PEs) in early (age 13, N = 6705) and late (age 18, N = 4676) adolescence, rated from semi-structured interviews. We used logistic regression to examine associations between cat ownership and PEs, adjusting for several sociodemographic and socioeconomic factors, household characteristics and dog ownership. Missing data were handled via multiple imputation.

RESULTS

Cat ownership during pregnancy was not associated with PEs at age 13 years [adjusted odds ratio (OR) 1.15, 95% confidence interval (CI) 0.97-1.35] or 18 years (OR 1.08, 95% CI 0.86-1.35). Initial univariable evidence that cat ownership at ages 4 and 10 years was associated with PEs at age 13 years did not persist after multivariable adjustment (4 years: OR 1.18, 95% CI 0.94-1.48; 10 years: OR 1.12, 95% CI 0.92-1.36). There was no evidence that childhood cat ownership was associated with PEs at age 18 years.

CONCLUSIONS

While pregnant women should continue to avoid handling soiled cat litter, given possible T. gondii exposure, our study strongly indicates that cat ownership in pregnancy or early childhood does not confer an increased risk of later adolescent PEs.

Socioeconomic status at birth and risk for first episode psychosis in rural Ireland: Eliminating the features of urbanicity in the Cavan-Monaghan First Episode Psychosis Study (CAMFEPS)

BACKGROUND

There is a paucity of research on the relationship between social environment at birth and risk for psychosis in rural settings. This study examined the relationship between individual- and neighbourhood-level socioeconomic indicators proximal to the time of birth and risk for a first psychotic episode in a rural context using a prospective dataset of unusual epidemiological completeness.

METHODS

A matched case-control design was used. 186 cases were identified from the Cavan-Monaghan First Episode Psychosis Study (CAMFEPS) and 679 age- and sex-matched controls from the same rural setting were identified and analysed for relationships with individual and neighbourhood-level socioeconomic indicators at the level of Electoral Divisions.

RESULTS

While neither the distribution nor the ordinal scale of parental social class differed between cases and controls, logistic regression revealed both parental social class III and increasing level of rurality to be associated (p≤0.05) with reduced risk for affective psychosis. There was a prominent relationship (p<0.001) between lower parental social class and older age at first presentation [mean age at first presentation for all psychoses: social class I, 22.8; social class VI, 44.3].

CONCLUSIONS

These findings indicate modest effects of individual- and neighbourhood-level socioeconomic indicators and risk for psychosis by place at birth within a rural environment. Thus, these factors are not confined to large urban settings and apply across the urban-rural continuum. The substantive finding in relation to age at first presentation may indicate that a gradient of socioeconomic position is influential on delay in presentation to mental health services.

Schizophrenia and Suicide Attempts: Findings from a Representative Community-Based Canadian Sample

This study examined factors associated with suicide attempts among those with schizophrenia (n = 101) versus those without (n = 21,643) in a representative sample of noninstitutionalized Canadians. The lifetime prevalence of suicide attempts among persons with schizophrenia was 39.2% versus 2.8% of nonafflicted individuals. After adjusting for sociodemographics, childhood adversities, substance abuse/dependence, depression/anxiety, and chronic pain, those with schizophrenia had 6 times the odds (OR = 6.47) of attempting suicide. Among persons with schizophrenia, suicide attempts were associated with female gender (OR = 4.59), substance abuse/dependence (OR = 6.31), depression (OR = 4.93), and childhood physical abuse (OR = 5.75). Community-dwelling persons with schizophrenia appear to be at high risk for suicide attempts.

Social class at birth and risk of psychosis

BACKGROUND

Individuals with psychotic disorders are represented more in the lower social classes, yet there is conflicting evidence to whether these individuals drift into the lower social classes or whether lower social class is a risk factor for developing psychosis. The aim of this study was to examine whether the social class at birth is a risk factor for developing psychosis.

METHODS

We included individuals with a first episode of psychosis (FEP) whose social class at birth was determined from birth records. We employed a case-control study design and also compared the distribution of the social classes at birth of the cases to that of the general population.

RESULTS

A total of 380 individuals with an FEP and 760 controls were included in the case-control study. The odds ratio for developing an FEP associated with social class (low vs high) was .62 (95% confidence interval (CI): .46-.85, p < .001), indicating that individuals from a lower social class at birth have a reduced risk of psychosis. Individuals born between 1961 and 1980 with an FEP were more likely to be from a higher social class at birth compared to the general population (60.8% vs 36.7%, χ(2) = 60.85, df = 1, p < .001). However, this association was not observed for those born between 1981 and 1990.

CONCLUSION

A higher social class at birth is associated with a greater risk for developing a psychotic disorder; however, this effect may show temporal variation.

Environmental factors and the age at onset in first episode psychosis

OBJECTIVE

Factors that influence the age at onset in psychotic disorders could provide valuable insights into precipitating or causative factors of the disorder. Despite being established risk factors, it is not yet known whether migration status, place of birth, social class at birth and season of birth influence the age at onset of psychotic disorders. This study aimed to determine whether these environmental factors, in addition to cannabis abuse and obstetric complications, influence the age at onset. Additionally, we investigated whether environmental factors could have a cumulative effect on the age at onset.

METHOD

Data was obtained from two first episode of psychosis (FEP) cohort studies. Diagnosis was established using the Structured Clinical Interview for DSM IV diagnoses.

RESULTS

The age at onset was determined for 555 individuals with a FEP and the median age at onset was 27.3years. Individuals with a history of cannabis abuse had an earlier age at onset by nearly six years. There was a trend for a history of obstetric complications to be associated with a younger age at onset by 2.7years and this was significant in the subgroup with a family history of psychosis. Social class at birth, migration status, place of birth and season of birth were not associated with the age at onset. Exposure to a higher number of environmental factors was associated with an earlier age at onset.

CONCLUSIONS

Cannabis and obstetric complications are associated with an earlier age at onset and there appears to be a cumulative effect of exposure to multiple environmental factors.

Common or distinct pathways to psychosis? A systematic review of evidence from prospective studies for developmental risk factors and antecedents of the schizophrenia spectrum disorders and affective psychoses

BACKGROUND

Identifying the unique and shared premorbid indicators of risk for the schizophrenia spectrum disorders (SSD) and affective psychoses (AP) may refine aetiological hypotheses and inform the delivery of universal versus targeted preventive interventions. This systematic review synthesises the available evidence concerning developmental risk factors and antecedents of SSD and AP to identify those with the most robust support, and to highlight remaining evidence gaps.

METHODS

A systematic search of prospective birth, population, high-risk, and case-control cohorts was conducted in Medline and supplemented by hand searching, incorporating published studies in English with full text available. Inclusion/exclusion decisions and data extraction were completed in duplicate. Exposures included three categories of risk factors and four categories of antecedents, with case and comparison groups defined by adult psychiatric diagnosis. Effect sizes and prevalence rates were extracted, where available, and the strength of evidence synthesised and evaluated qualitatively across the study designs.

RESULTS

Of 1775 studies identified by the search, 127 provided data to the review. Individuals who develop SSD experience a diversity of subtle premorbid developmental deficits and risk exposures, spanning the prenatal period through early adolescence. Those of greatest magnitude (or observed most consistently) included obstetric complications, maternal illness during pregnancy (especially infections), other maternal physical factors, negative family emotional environment, psychopathology and psychotic symptoms, and cognitive and motor dysfunctions. Relatively less evidence has accumulated to implicate this diversity of exposures in AP, and many yet remain unexamined, with the most consistent or strongest evidence to date being for obstetric complications, psychopathology, cognitive indicators and motor dysfunction. Among the few investigations affording direct comparison between SSD and AP, larger effect sizes and a greater number of significant associations are commonly reported for SSD relative to AP.

CONCLUSIONS

Shared risk factors for SSD and AP may include obstetric complications, childhood psychopathology, cognitive markers and motor dysfunction, but the capacity to distinguish common versus distinct risk factors/antecedents for SSD and AP is limited by the scant availability of prospective data for AP, and inconsistency in replication. Further studies considering both diagnoses concurrently are needed. Nonetheless, the prevalence of the risk factors/antecedents observed in cases and controls helps demarcate potential targets for preventative interventions for these disorders.

Do patterns of mental healthcare predict treatment failure in young people with schizophrenia? Evidence from an Italian population-based cohort study

OBJECTIVE

Little is known about the practice of predicting community-based care effectiveness of patients affected by schizophrenic disorders. We assessed predictors of treatment failure in a large sample of young people affected by schizophrenia.

METHODS

A cohort of 556 patients aged 18-35 years who were originally diagnosed with schizophrenia during 2005-2009 in a Mental Health Service (MHS) of the Italian Lombardy Region was identified. Intensity of mental healthcare received during the first year after index visit (exposure) was measured by patients' regularity in MHS attendance and the length of time covered with antipsychotic drug therapy. Patients were followed from index visit until 2012 for identifying hospital admission for mental disorder (outcome). A proportional hazards model was fitted to estimate the HR and 95% CIs for the exposure-outcome association, after adjusting for several covariates. A set of sensitivity analyses were performed in order to account for sources of systematic uncertainty.

RESULTS

During follow-up, 144 cohort members experienced the outcome. Compared with patients on low coverage with antipsychotic drugs (≤ 4 months), those on intermediate (5-8 months) and high (≥ 9 months) coverage, had HRs (95% CI) of 0.94 (0.64 to 1.40) and 0.69 (0.48 to 0.98), respectively. There was no evidence that regular attendance at the MHS affected the outcome.

CONCLUSIONS

Patients in the early phase of schizophrenia and their families should be cautioned about the possible consequences of poor antipsychotic adherence. Physicians and decision makers should increase their contribution towards improving mental healthcare.

Is there evidence that social class at birth increases risk of psychosis? A systematic review

BACKGROUND

In the 1950s, researchers showed an association between low socio-economic status (SES) and psychosis. Two competing theories social causation and social drift were proposed to explain the findings. In the intervening years, contrasting evidence emerged as some studies showed no association between SES and schizophrenia. At present, the nature of the relationship is still unclear; currently, there are no reviews in the literature examining the association between social class at birth and psychosis.

AIM

To search the literature to clarify the relationship between social class at birth, measured by paternal occupation at birth, and the risk of adult-onset psychosis.

METHODS

A systematic search of the literature using a combination of keywords in Group 1 together with the keywords in Group 2 was performed in October 2012 in the following online databases: (a) MEDLINE (1946-2012), (b) PubMed, (c) Embase (1980-2012), (d) PsycINFO (1806-2012) and (e) Web of Science (1899-2012). Reference lists were also hand searched. The search provided 3,240 studies; following screening of the titles and abstracts by inclusion and exclusion criteria and quality assessment of the full text, 14 studies were identified to be appropriate for the review. The keywords used for the search were as follows: Group 1 - social class, social status, socioeconomic, socio-economic, SES; Group 2 - psychosis, psychoses, schizophrenia.

RESULTS

Seven studies showed an association between low SES and psychosis. Four studies showed no association, and three studies showed an association with high SES.

CONCLUSION

There is not enough evidence to support the association between social class and psychosis. While some findings showed an association between low social class and psychosis, there were a number of conflicting studies showing no association or a link with higher social class. Interestingly, the results followed a temporal pattern, as all the studies conducted after 2001 supported an association between low SES at birth and psychosis. Four of the six studies employed a prospective design with large sample populations, indicating the need for further investigation.

Determinants of duration of untreated psychosis in an Irish catchment area sample

Objective: To examine the variables that influence of duration of untreated psychosis (DUP) prior to presentation in persons with a first episode of psychosis.

Method: Prospective examination of consecutive first presentations with DSM-IV psychosis attending a community based psychiatric service.

Results: One hundred and seventy-one patients had an average duration of untreated psychosis of 18 months and a median of five months. The mean duration of untreated mania was 1.5 months, median 0.75 months. DUP was predicted by social withdrawal and diagnosis in the total group and by prodrome in the schizophrenia/schizophreniform group. DUP was not associated with age at onset of psychosis, educational years or living status.

Conclusions: There are significant differences in DUP between diagnostic groups. Increased social withdrawal is associated with a longer DUP.

Identifying aspects of neighbourhood deprivation associated with increased incidence of schizophrenia

BACKGROUND

Several studies have found an association between area deprivation and incidence of schizophrenia. However, not all studies have concurred and definitions of deprivation have varied between studies. Relative deprivation and inequality seem to be particularly important, but which aspects of deprivation or how this effect might operate is not known.

METHODS

The Lambeth Early Onset case register is a database of all cases of first episode psychosis aged 16 to 35years from the London Borough of Lambeth, a highly urban area. We identified 405 people with first onset schizophrenia who presented between 2000 and 2007. We calculated the overall incidence of first onset schizophrenia and tested for an association with area-level deprivation, using a multi-domain index of deprivation (IMD 2004). Specific analyses into associations with individual sub-domains of deprivation were then undertaken.

RESULTS

Incidence rates, directly standardized for age and gender, were calculated for Lambeth at two geographical levels (small and large neighbourhood level). The Poisson regression model predicting incidence rate ratios for schizophrenia using overall deprivation score was statistically significant at both levels after adjusting for ethnicity, ethnic density, population density and population turnover. The incidence rate ratio for electoral ward deprivation was 1.03 (95% CI=1.004-1.04) and for the super output area deprivation was 1.04 (95% CI=1.02-1.06). The individual domains of crime, employment deprivation and educational deprivation were statistically significant predictors of incidence but, after adjusting for the other domains as well as age, gender, ethnicity and population density, only crime and educational deprivation, remained statistically significant. Low income, poor housing and deprived living environment did not predict incidence.

CONCLUSIONS

In a highly urban area, an association was found between area-level deprivation and incidence of schizophrenia, after controlling for age, gender, ethnicity and population density; high crime and low levels of education accounted for this. As both of these are potentially modifiable, this suggests a possible means to reduce the incidence of schizophrenia.

Predicting changes in delusional ideation: the role of mindfulness and negative schemas

OBJECTIVES

Understanding factors that contribute to delusional ideation has important clinical implications. This study looked at the impact of mindfulness and negative schemas on changes in delusional ideation over time.

DESIGN

A sample of University students was selected to investigate processes related to delusional ideation in a non-clinical sample.

METHOD

A web-based survey was completed by 700 University students, 204 of whom completed a second identical survey after 6 months, to comprise the longitudinal sample.

RESULTS

Results from the study demonstrated that negative schemas and mindfulness were related to changes in delusional ideation over time and support was found for a mediated model, whereby mindfulness mediated the impact of schemas on the outcome.

CONCLUSIONS

The findings point to the importance of mindfulness as an intervention for preventing non-clinical delusional ideation transitioning into clinical delusions.

The relationship between risk of hospitalization for schizophrenia, SES, and cognitive functioning

Although most studies find low socioeconomic status (SES) to be associated with prevalence of schizophrenia, incidence studies do not generally support this, and some even report an inverse association. The objective of the current historical prospective study was to examine the relationship between SES, cognitive functioning, and risk of hospitalization for schizophrenia in a population-based sample of Israeli adolescents. Subjects were 811 487 adolescents, assessed by the Israeli military draft board for socio-demographic factors and cognitive functioning. Data on later hospitalization for schizophrenia were obtained from a population-based hospitalization registry. Findings indicated that when simply examining SES and schizophrenia, lower SES was associated with greater risk of hospitalization for schizophrenia (Hazard Ratio [HR] = 1.193, 95% CI = 1.091-1.303). When dividing the cohort into low, average, and high cognitive functioning, SES did not influence the risk for schizophrenia among individuals with high and average cognitive functioning, whereas among individuals with low cognitive functioning, high SES was found to slightly increase the risk for schizophrenia (HR = 1.21, 95% CI = 1.03-1.42). One possible explanation for this finding might be that among individuals from low socioeconomic backgrounds, low IQ may reflect decreased opportunities related to SES, whereas among individuals from high SES backgrounds, low IQ might reflect risk for later psychopathology.

Migration and psychotic disorders

The incidence of psychotic disorders is extremely high in several immigrant groups in Europe. This article describes the epidemiological evidence for increased incidence rates among immigrants compared with nonimmigrant populations and explores possible explanations for this excess risk. Potential causes not only involve factors acting at the level of the individual, but encompass the broader social context of neighborhoods and ethnic groups. Growing up and living in a disadvantaged ethnic minority position, characterized by a low social status, high degree of discrimination against the group and low neighborhood ethnic density, may lead to an increased risk of psychotic disorders, especially when individuals reject their minority status and when their social resources are insufficient to buffer the impact of adverse social experiences. Future research should refine measures of the social context, adopt a life-course perspective and should integrate social and neurobiological pathways.

Obstetrical complications, social class and type of schizophrenia

The emerging neurodevelopmental model posits that prenatal and perinatal factors can play an etiological role in schizophrenia. Consistently, the research on obstetrical complications (OCs) reports an association with the development of more severe schizophrenic symptoms. Low socioeconomic status (SES) has also been linked to both limited prenatal healthcare and to worse prognosis of schizophrenic symptoms. A large sample (n=437) of patients from a state hospital population in the U. S. was screened for study variables. A sequential analysis was conducted, first applying cross tabulations using the chi-square test, and then building separate logit models for poor and nonpoor patients. The cross tabulations indicated an association between OCs and negative symptoms for poor schizophrenic patients, but not for nonpoor patients. Multivariate logit models further supported this result. This is the first study to examine the interaction of OCs, schizophrenic symptomatology and SES of origin.

The environment and susceptibility to schizophrenia

In the present article the putative role of environmental factors in schizophrenia is reviewed and synthesized. Accumulating evidence from recent studies suggests that environmental exposures may play a more significant role in the etiopathogenesis of this disorder than previously thought. This expanding knowledge base is largely a consequence of refinements in the methodology of epidemiologic studies, including birth cohort investigations, and in preclinical research that has been inspired by the evolving literature on animal models of environmental exposures. This paper is divided into four sections. In the first, the descriptive epidemiology of schizophrenia is reviewed. This includes general studies on incidence, prevalence, and differences in these measures by urban-rural, neighborhood, migrant, and season of birth status, as well as time trends. In the second section, we discuss the contribution of environmental risk factors acting during fetal and perinatal life; these include infections [e.g. rubella, influenza, Toxoplasma gondii (T. gondii), herpes simplex virus type 2 (HSV-2)], nutritional deficiencies (e.g., famine, folic acid, iron, vitamin D), paternal age, fetal/neonatal hypoxic and other obstetric insults and complications, maternal stress and other exposures [e.g. lead, rhesus (Rh) incompatibility, maternal stress]. Other putative neurodevelopmental determinants, including cannabis, socioeconomic status, trauma, and infections during childhood and adolescence are also covered. In the third section, these findings are synthesized and their implications for prevention and uncovering biological mechanisms, including oxidative stress, apoptosis, and inflammation, are discussed. Animal models, including maternal immune activation, have yielded evidence suggesting that these exposures cause brain and behavioral phenotypes that are analogous to findings observed in patients with schizophrenia. In the final section, future studies including new, larger, and more rigorous epidemiologic investigations, and research on translational and clinical neuroscience, gene-environment interactions, epigenetics, developmental trajectories and windows of vulnerability, are elaborated upon. These studies are aimed at confirming observed risk factors, identifying new environmental exposures, elucidating developmental mechanisms, and shedding further light on genes and exposures that may not be identified in the absence of these integrated approaches. The study of environmental factors in schizophrenia may have important implications for the identification of causes and prevention of this disorder, and offers the potential to complement, and refine, existing efforts on explanatory neurodevelopmental models.

Beyond the first episode: candidate factors for a risk prediction model of schizophrenia

Many early psychosis services are financially compromised and cannot offer a full tenure of care to all patients. To maintain viability of services it is important that those with schizophrenia are identified early to maximize long-term outcomes, as are those with better prognoses who can be discharged early. The duration of untreated psychosis remains the mainstay in determining those who will benefit from extended care, yet its ability to inform on prognosis is modest in both the short and medium term. There are a number of known or putative genetic and environmental risk factors that have the potential to improve prognostication, though a multivariate risk prediction model combining them with clinical characteristics has yet to be developed. Candidate risk factors for such a model are presented, with an emphasis on environmental risk factors. More work is needed to corroborate many putative factors and to determine which of the established factors are salient and which are merely proxy measures. Future research should help clarify how gene-environment and environment-environment interactions occur and whether risk factors are dose-dependent, or if they act additively or synergistically, or are redundant in the presence (or absence) of other factors.

Influence of early life factors on social inequalities in psychiatric outcomes among young adult Norwegian men

BACKGROUND

Social inequalities in health can to a substantial degree be explained by social causation. However, indirect selection by early life factors has been suggested. The main aim of this study was to estimate how much adult social gradients in selected psychiatric outcomes depended on parental and individual characteristics in early life.

METHODS

The population comprised all males born in Norway 1967-71 (n = 170 678). We compiled data on several social and biological variables from birth onwards from different national registers. Health outcomes were collected from the Cause of Death Register (suicide) and the Labour and Welfare Administration (psychiatric disability, psychiatric sickness absence). Indicator of socio-economic position was education level at the age of 28 years. Men were followed up between 4 and 9 years from the age of 29 years.

RESULTS

Crude rates per 100 000 person-years were 21.8 (suicide), 145.7 (disability) and 1164.7 (sickness absence). Social inequalities were strong and consistent for all outcomes. Parental and individual characteristics accounted for a substantial part of the social inequalities in neurosis or personality disorder disability (44.1%) and a moderate role for inequalities in psychiatric sickness absence (25.6%), schizophrenia disability (20.7%) and suicide (17.4%). General ability at the age of 18 years had strongest influence on the social health gradients. Suicide and schizophrenia disability were associated with a combination of high parental and low own education level.

CONCLUSION

This study indicates that indirect selection explains a substantial part of social inequalities in certain psychiatric outcomes and that early life prevention is important to reduce health gradients.

Schizophrenia and the city: A review of literature and prospective study of psychosis and urbanicity in Ireland

Urbanicity has been repeatedly associated with increased incidence of schizophrenia. This article (a) presents results of a prospective study of urbanicity and schizophrenia in Ireland and (b) reviews the literature relating to urbanicity and schizophrenia. We prospectively compared incidence of schizophrenia and other psychoses in urban and rural catchment areas (over 4years and 7years, respectively) using face-to-face, DSM-III-R diagnostic interviews. Incidence of schizophrenia in males was higher in urban compared to rural areas, with an age-adjusted incidence rate ratio (IRR) of 1.92 (1.52-2.44) for males and 1.34 (1.00-1.80) for females. Incidence of affective psychosis was lower in urban compared to rural areas for males (IRR 0.48; 0.34-0.67) and females (IRR 0.60; 0.43-0.83). These findings are consistent with the literature, which provides persuasive evidence that risk for schizophrenia increases with urban birth and/or upbringing, especially among males. Register-based studies support this conclusion more consistently than studies using face-to-face diagnostic interviews, the difference being related to power. The mechanism of association is unclear but may relate to biological or social/environmental factors or both, acting considerably before psychotic symptoms manifest. There is a diversity of potential candidates, including air pollution, cannabis and social exclusion. Urbanicity may have a synergistic effect with genetic vulnerability. Future research is likely to focus on the relationship between urbanicity and neural maldevelopment, the possibility of rural protective factors (e.g. social capital, low social fragmentation), urbanicity in developing countries, cultural variables and geographical location, and associations between urbanicity and other disorders (e.g. affective psychosis).

Effect of socioeconomic status and parents' education at birth on risk of schizophrenia in offspring

Although it is known that schizophrenia is associated with social class, controversy exists as to the nature of this association. The authors studied the incidence of schizophrenia in relation to social class at birth in a population-based cohort of 88,829 offspring born in Jerusalem in 1964-1976. They constructed a six-point scale to index social class, based on paternal occupation at the time of birth, with each of 108 occupations being ranked by mean education. Cox proportional hazards methods were used in adjusting for sex, parents' ages, duration of marriage and birth order. Linkage with Israel's Psychiatric Registry identified 637 people admitted to psychiatric care facilities with schizophrenia-related diagnoses, before 1998. There was no gradient of risk for schizophrenia associated with social class at birth; however, offspring of fathers in the lowest social class showed a modest increase in risk (adjusted Relative Risk = 1.4; 95% Confidence interval = 1.1-1.8, P = 0.002). These data suggest that in contrast to many other health outcomes, there is not a continuous gradient for increasing schizophrenia with decreasing social class of origin. Instead, a modest increase in risk for schizophrenia was observed only for those born at the bottom of the social ladder.

Socioeconomic status at birth is associated with risk of schizophrenia: population-based multilevel study

BACKGROUND

Inconsistent findings obscure understanding the relationship between socioeconomic status (SES) and schizophrenia. The aim of the current study was to test the association between individual and community SES at birth and risk of schizophrenia.

METHOD

Population-based longitudinal follow forward study of a 13-year birth cohort (n = 71 165). Effects of individual and community socioeconomic variables were examined using multilevel regression in MLwiN.

RESULTS

Years of education of fathers and mothers, respectively, (0-8 vs 13+ odds ratio [OR] = 1.17, P < .0001; OR = 1.14, P < .001) lower occupational status of fathers (OR = 1.29, P = .036), and poorer residential area SES (OR = 1.26, P = .012) were risk factors for schizophrenia.

CONCLUSIONS

Individual- and community-level SES at the time of birth are associated with an increased risk of schizophrenia.

First psychiatric hospitalizations in the US military: the National Collaborative Study of Early Psychosis and Suicide (NCSEPS)

BACKGROUND

Military samples provide an excellent context to systematically ascertain hospitalization for severe psychiatric disorders. The National Collaborative Study of Early Psychosis and Suicide (NCSEPS), a collaborative study of psychiatric disorders in the US Armed Forces, estimated rates of first hospitalization in the military for three psychiatric disorders: bipolar disorder (BD), major depressive disorder (MDD) and schizophrenia.

METHOD

First hospitalizations for BD, MDD and schizophrenia were ascertained from military records for active duty personnel between 1992 and 1996. Rates were estimated as dynamic incidence (using all military personnel on active duty at the midpoint of each year as the denominator) and cohort incidence (using all military personnel aged 18-25 entering active duty between 1992 and 1996 to estimate person-years at risk).

RESULTS

For all three disorders, 8723 hospitalizations were observed in 8,120,136 person-years for a rate of 10.7/10,000 [95% confidence interval (CI) 10.5-11.0]. The rate for BD was 2.0 (95% CI 1.9-2.1), for MDD, 7.2 (95% CI 7.0-7.3), and for schizophrenia, 1.6 (95% CI 1.5-1.7). Rates for BD and MDD were greater in females than in males [for BD, rate ratio (RR) 2.0, 95% CI 1.7-2.2; for MDD, RR 2.9, 95% CI 2.7-3.1], but no sex difference was found for schizophrenia. Blacks had lower rates than whites of BD (RR 0.8, 95% CI 0.7-0.9) and MDD (RR 0.8, 95% CI 0.8-0.9), but a higher rate of schizophrenia (RR 1.5, 95% CI 1.3-1.7).

CONCLUSIONS

This study underscores the human and financial burden that psychiatric disorders place on the US Armed Forces.

The power gap: Freedom, power and mental illness

Up to one in four individuals in the US meet the diagnostic criteria for a mental illness in any given year and a significant proportion have severe or recurring illnesses (e.g. schizophrenia). Despite this prevalence, mental health services remain poorly funded, mental illness remains misunderstood and individuals with recurring illness are constrained to live lives characterized by isolation, under-employment, stigma and denial of rights. Here I examine the idea that this situation is attributable, at least in part, to the ways in which the freedom and power of the mentally ill are undermined by a range of factors, including: (i) dispersion of political power amongst interest groups, which, combined with the relatively wide distribution of the 'interest' of mental illness, has the paradoxical result that mental health interest groups do not command political power proportional to the number affected; (ii) systematic exclusion of the mentally ill from full participation in civic, social and political life (structural violence), resulting in a lack of emphasis on mental health on political agendas and the exclusion of certain policy options as possible responses and (iii) difficulties the mentally ill may experience recognizing or articulating their own needs the absence of effective health-care systems, and the absence of knowledge about alternative systems. I argue that the enhancement of individual agency is central to efforts to address this power gap, including: (i) rights-based approaches, involving the enhancement of national mental health legislation, improvement of advocacy, empowerment and guardianship processes and development of governance, accountability and quality procedures in mental health services; (ii) approaches based on enhancing direct political participation, including voter-registration programmes and development of larger, more effective interest groups and (iii) additional approaches, including increasing accountability throughout services, recognizing the effects of socio-political change on the context of care and adapting the concept of 'soft power' to strengthen advocacy programmes.

Environmental risk factors for psychosis

Genetic factors are clearly important in the etiology of schizophrenia, but the environment in which an individual's genes find expression is also crucial to the development of the illness. In this review of environmental risk factors for schizophrenia, we consider risks operating prenatally and perinatally, during childhood, and then later in life prior to illness onset. Some of these risk factors have been well documented, for example, early hazards causing fetal growth retardation or hypoxia, and hazards nearer the onset of illness like drug abuse and migration. Others are much less certain. The importance of interaction between genetic and environmental risk is, however, undoubtedly important and there is emerging evidence for this from a range of sources. As the etiology of schiz-ophrenia is unraveled, the picture becomes more complex, but also more obviously relevant to the plight of the individual patient.

The public mental health significance of research on socio-economic factors in schizophrenia and major depression

This paper reviews the epidemiological research evidence on the role of socio-economic factors in the origins and disease experience of schizophrenia and major depression. The studies were conducted in different countries over many years. Although their findings are divided in their support of either the social causation or the drift hypothesis, all of them agree that persons with these disorders are at high disadvantage in society. Several factors for this have been identified. These studies provide the rationale for community-based interventions that have to be guided by principles of equity in the distribution of resources and grounded in biopsychosocial models of care that comprehensively answer the needs of the affected populations.

Structural violence and schizophrenia

Despite clear evidence of a substantial biological basis to schizophrenia, there is also evidence that social, economic and political factors have considerable relevance to the clinical features, treatment and outcome of the illness. Individuals from lower socio-economic groups have an earlier age at first presentation and longer durations of untreated illness, both of which are associated with poor outcome. Individuals with schizophrenia are over-represented in the homeless population. Migration is associated with increased rates of mental illness, including schizophrenia, and this relationship appears to be mediated by psycho-social factors, including difficulties establishing social capital in smaller migrant groups. Individuals with schizophrenia are substantially over-represented amongst prison populations, and imprisonment increases the disability and stigma associated with mental illness, and impedes long-term recovery. The adverse effects of these social, economic and societal factors, along with the social stigma of mental illness, constitute a form of 'structural violence' which impairs access to psychiatric and social services and amplifies the effects of schizophrenia in the lives of sufferers. As a result of these over-arching social and economic factors, many individuals with schizophrenia are systematically excluded from full participation in civic and social life, and are constrained to live lives that are shaped by stigma, isolation, homelessness and denial of rights. There are urgent needs for (1) the development of enhanced aetiological models of schizophrenia, which elucidate the interactions between genetic risk and social environment, and can better inform bio-psycho-social approaches to treatment; (2) a renewal of emphasis on the United Nations' "Principles for the Protection of Persons with Mental Illness" and related legislative measures in individual countries; and (3) continued study and examination of the impact of social, economic and political structures on the clinical features and outcome of mental illnesses.

Confidentiality and the duties of care

Doctors have an ethical and legal duty to respect patient confidentiality. We consider the basis for this duty, looking particularly at the meaning and value of autonomy in health care. Enabling patients to decide how information about them is disclosed is an important element in autonomy and helps patients engage as active partners in their care. Good quality data is, however, essential for research, education, public health monitoring, and for many other activities essential to provision of health care. We discuss whether it is necessary to choose between individual rights and the wider public interest and conclude that this should only rarely be necessary. The paper makes some recommendations on practical steps which could help ensure that good quality information is available for work which benefits society and the public health, while still enabling patients' autonomy to be respected.

A classification of sociomedical health indicators: perspectives for health administrators and health planners

The conceptualization and operationalization of measures of health status are considered. Health indicators are conceived as a subset of social indicators, and therefore, as any social indicator, they are viewed as derivative from social issues. The interrelationships of different frames of reference for defining and measuring health that have accompained three distinct health problem patterns in the United States are viewed from a developmental perspective. Mortality and morbidity rates, the traditional health indicators, by themselves no longer serve to assess health status in developed nations. Their deficiencies as indicators serve as background for a classification schema for sociomedical health status indicators that relates health definition frames of reference, measures of health status, and health problems. The role of a group of health indicators-sociomedical heath indicators-in the current formulation of health status measures is assessed.