Urban living and psychosis--an overview

Risk and protective factors for severe mental disorders in Asia

Among 369 diseases and injuries, the years lived with disability (YLDs) and disability-adjusted life-years (DALYs) rates for severe mental illnesses (SMIs) are within the top 20 %. Research on risk and protective factors for SMIs is critically important, as acting on modifiable factors may reduce their incidence or postpone their onset, while early detection of new cases enables prompt treatment and improves prognosis. However, as most of the studies on these factors are from Western countries, the findings are not generalizable across ethnic groups. This led us to conduct a systematic review of the risk and protective factors for SMIs identified in Asian studies. There were common factors in Asian and Western studies and unique factors in Asian studies. In-depth knowledge of these factors could help reduce disability, and the economic and emotional burden of SMIs. We hope that this review will inform future research and policy-making on mental health in Asian countries.

Urbanization and psychosis: an update of recent evidence

PURPOSE OF REVIEW

Urbanization, a complex global phenomenon, has a significant bearing on schizophrenia/psychosis burden through various socioeconomic and environmental factors. This review focuses on recent evidence (2019-2023) linking urbanization, schizophrenia, and the role of green space.

RECENT FINDINGS

This review analyzed 43 articles that examined the correlation between urban birth or upbringing, urban living (urbanicity), and various schizophrenia/psychosis-related outcomes such as incidence, psychotic experiences, etc. The studies showed differing results across geographical locations. Socioeconomic factors like area deprivation, migrant status (ethnic density) and social fragmentation were independently associated with the risk of schizophrenia/psychosis irrespective of urbanicity. More recently, environmental factors such as green space reduction and air pollution have been explored in urban living conditions and were positively associated with an increased risk of schizophrenia/psychosis.

SUMMARY

There is a need for further investigation in low and middle-income countries. The impact of urbanization-related factors and green space on the risk of schizophrenia/psychosis calls for appropriate governmental commitments toward structured and healthy urban planning.

Racial microaggressions and major discriminatory events explain ethnoracial differences in psychotic experiences

Few empirical studies have examined whether exposure to major racial discrimination explains ethnoracial disparities in psychosis outcomes and none to our knowledge have done so in the U.S. or have examined the role of other forms of racism such as racial microaggressions. The present study examined ethnoracial differences in self-reported psychotic experiences (PE) among 955 college students in an urban environment in the Northeastern U.S., and the degree to which major experiences of racial discrimination and racial microaggressions explains ethnoracial differences in PE. Mean scores on self-report inventories of PE and distressing PE (i.e., Prodromal Questionnaire (PQ)), major experiences of racial discrimination (EOD), and racial and ethnic microaggressions (REMS) were compared across 4 ethnoracial groups (White, Black, Asian, and Latina/o). Results from parallel mediation linear regression models adjusted for immigrant status, age, gender, and family poverty using the Hayes PROCESS application indicated ethnoracial differences in PE were explained independently by both forms of racism. Specifically, Black young people reported higher mean levels of PE, and distressing PE than both White and Latina/o people and the difference in PE between Black and White and Black and Latino/a young people was significantly explained by both greater exposure to racial microaggressions and major racial discriminatory experiences among Black people. This study re-emphasizes the explanatory role of racism, in its multiple forms, for psychosis risk among Black young populations in the US. Anti-racism interventions at both structural and interpersonal levels are necessary components of public health efforts to improve mental health in Black populations.

Urbanicity, posttraumatic stress disorder, and effect modification by socioeconomic position: A nested case-control study of the Korean National Health Insurance Database

BACKGROUND

We aimed to estimate the association between urbanicity and the onset of posttraumatic stress disorder (PTSD) and to investigate heterogeneity therein according to age and socioeconomic position (SEP).

METHODS

We analyzed administrative data from the Korean National Health Insurance Database for patients with PTSD from 2004 to 2018 (N = 109,230) and for a 1:4 sample of age-, sex-, and enrollment year-matched controls. Information on eligibility, SEP (proxied by insurance premium), place of residence, diagnosis, and medical claims was obtained. Urbanicity of administrative districts was assessed using data from the Korean Statistical Information Service, 2005-2018. We estimated hazard ratios (HRs) from baseline and time-dependent models. Subgroup analyses and polynomial splines were used to investigate heterogeneity by age and SEP.

RESULTS

Urbanicity was associated with an increased risk of PTSD (per 10%p increase, HR = 1.056, 95% CI 1.050-1.061). A positive association was estimated among patients aged 0-29 years (HR = 1.115, CI 1.106-1.124), while negative associations were estimated among patients aged 30-64 years (HR = 0.990, CI 0.987-0.994) and 65 years or older (HR = 0.992, CI 0.979-1.014). The estimated associations with urbanicity were more prominent at the extremes of SEP, but only among younger participants.

CONCLUSION

Urban residence was associated with an increased risk of PTSD diagnosis. The estimated association was larger among younger individuals (but not among middle-aged and older individuals). Among younger individuals, the estimated association was larger at both extremes of SEP.

Psychotic experiences among Black college students in the United States: The role of socioeconomic factors and discrimination

BACKGROUND

Psychosis is more prevalent among Black individuals compared with White individuals. However, it is unknown whether this disparity exists among college populations in the United States, and if so, what factors contribute to the disparity.

METHODS

We analyzed data from Black and White young adult students using the Health Minds Study (2020-2021), which is a survey administered at 140 colleges in the U.S. Using mediation analysis, we examined the extent to which the relation between race and psychotic experiences was mediated by socioeconomic factors (past and current financial distress, food insecurity, parental education) and discrimination.

RESULTS

Approximately 38 % of Black students and 30 % of White students reported lifetime psychotic experiences. Including all socioeconomic factors together in the same model accounted for just over half (50.2 %) the association between race and psychotic experiences. We then conducted additional analyses examining discrimination, all the socioeconomic factors plus discrimination accounted for 81.5 % of the association between race and psychotic experiences. When disentangling the mediators, food insecurity and discrimination accounted for the largest percentages of the association. The effects of past financial distress and parental education were modified by race.

CONCLUSION

Black college students were more likely to report lifetime psychotic experiences than their White counterparts. Moreover, socioeconomic factors and discrimination made significant contributions to this racial difference.

From scary places to therapeutic landscapes: Voices from the community of people living with schizophrenia

This article discusses how people living with schizophrenia experience, understand, and respond to their urban environment. Our study relies on experiential photo-voice data gathered with a sample of six people diagnosed with schizophrenia and living in non-institutional settings in Montréal, Canada, to identify how individuals in this community perceive the urban landscape. We adopt a therapeutic landscapes' framework that explores the urban fabric at three levels: physical, social, and symbolic. Research participants identified both health-denying and health-enhancing places within ordinary urban landscapes. Landscapes identified as health-denying are characterized by environmental stressors and loss of control, with construction sites an example highlighted by participants. Healing and restorative landscapes, as identified by participants, were physically attractive or quiet, socially safe and welcoming, and symbolically affirmative of one's identity, all factors worthy of further study. The findings are also policy-relevant: they suggest that people living with schizophrenia and their clinicians can develop strategies to make health-enhancing uses of urban landscapes; and that urban policies and practices can foster urban environments conducive to enhanced health and well-being, both for the community of people living with schizophrenia and the wider population of urban dwellers.

Psychotic symptoms associate inversely with social support, social autonomy and psychosocial functioning: A community-based study

BACKGROUND

Population-based studies exploring psychotic symptoms (PS) show that their prevalence in the community is higher than previously thought. Psychosocial functioning and social support are poorer among people presenting clinical and subclinical PS.

AIMS

We aimed to estimate the prevalence rate of PS in Andalusia and to explore the association between PS and psychosocial functioning, social support and social autonomy in a Southern European population.

MATERIAL AND METHODS

This is a cross-sectional study. We undertook multi-stage sampling using different standard stratification techniques. Out of 5496 households approached, we interviewed 4507 (83.7%) randomly selected participants living in the autonomous region of Andalusia (Southern Spain). The Spanish version of the MINI International Neuropsychiatric Interview was used to elicit PS. We also gathered information on socio-demographic factors, suicidality risk, psychosocial functioning, social support and social autonomy.

RESULTS

The overall prevalence of PS was 6.7% (95% CI: 5.99-6.45). PS were associated with lower age (OR 0.975; 95% CI (0.967-0.983); p < .0001), female gender (OR = 1.346; 95% CI (1.05-1.07) p = .018), not living in a rural area (OR = 0.677; 95% CI (0.50-0.90) p = 0.009), lower social support (OR = 0.898; 95% CI (0.85-0.94) p < .0001), lower scores on social autonomy (OR = 0.889; 95% CI (0.79-1.00) p = .050), having an increased suicidality risk score (OR = 1.038; 95% CI (1.005-1.07); p = .023) and having lower scores on psychosocial functioning (OR = 0.956; 95% CI (0.95-0.96); p < 0.0001).

CONCLUSIONS

Social outcomes seem to be strongly inversely associated with PS in spite of presumed higher levels of social support among Southern European cultures.

Need for Ethnic and Population Diversity in Psychosis Research

This article aims to evaluate "racial", ethnic, and population diversity-or lack thereof-in psychosis research, with a particular focus on socio-environmental studies. Samples of psychosis research remain heavily biased toward Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies. Furthermore, we often fail to acknowledge the lack of diversity, thereby implying that our findings can be generalized to all populations regardless of their social, ethnic, and cultural background. This has major consequences. Clinical trials generate findings that are not generalizable across ethnicity. The genomic-based prediction models are far from being applicable to the "Majority World." Socio-environmental theories of psychosis are solely based on findings of the empirical studies conducted in WEIRD populations. If and how these socio-environmental factors affect individuals in entirely different geographic locations, gene pools, social structures and norms, cultures, and potentially protective counter-factors remain unclear. How socio-environmental factors are assessed and studied is another major shortcoming. By embracing the complexity of environment, the exposome paradigm may facilitate the evaluation of interdependent exposures, which could explain how variations in socio-environmental factors across different social and geographical settings could contribute to divergent paths to psychosis. Testing these divergent paths to psychosis will however require increasing the diversity of study populations that could be achieved by establishing true partnerships between WEIRD societies and the Majority World with the support of funding agencies aspired to foster replicable research across diverse populations. The time has come to make diversity in psychosis research more than a buzzword.

The association between ozone and fine particles and mental health-related emergency department visits in California, 2005-2013

Recent studies suggest that air pollutant exposure may increase the incidence of mental health conditions, however research is limited. We examined the association between ozone (O3) and fine particles (PM2.5) and emergency department (ED) visits related to mental health outcomes, including psychosis, neurosis, neurotic/stress, substance use, mood/affective, depression, bipolar, schizotypal/delusional, schizophrenia, self-harm/suicide, and homicide/inflicted injury, from 2005 through 2013 in California. Air monitoring data were provided by the U.S. EPA's Air Quality System Data Mart and ED data were provided by the California Office of Statewide Health Planning and Development. We used the time-series method with a quasi-Poisson regression, controlling for apparent temperature, day of the week, holidays, and seasonal/long-term trends. Per 10 parts per billion increase, we observed significant cumulative 7-day associations between O3 and all mental health [0.64%, 95% confidence interval (CI): 0.21, 1.07], depression [1.87%, 95% CI: 0.62, 3.15], self-harm/suicide [1.43%, 95% CI: 0.35, 2.51], and bipolar [2.83%, 95% CI: 1.53, 4.15]. We observed 30-day lag associations between O3 and neurotic disorder [1.22%, 95% CI: 0.48, 1.97] and homicide/inflicted injury [2.01%, 95% CI: 1.00, 3.02]. Same-day mean PM2.5 was associated with a 0.42% [95% CI: 0.14, 0.70] increase in all mental health, 1.15% [95% CI: 0.62, 1.69] increase in homicide/inflicted injury, and a 0.57% [95% CI: 0.22, 0.92] increase in neurotic disorders per 10 μg/m3 increase. Other outcomes not listed here were not statistically significant for O3 or PM2.5. Risk varied by age group and was generally greater for females, Asians, and Hispanics. We also observed seasonal variation for outcomes including but not limited to depression, bipolar, schizophrenia, self-harm/suicide, and homicide/inflicted injury. Ambient O3 or PM2.5 may increase the risk of mental health illness, though underlying biological mechanisms remain poorly understood. Findings warrant further investigation to better understand the impacts of air pollutant exposure among vulnerable groups.

The environmental enrichment model revisited: A translatable paradigm to study the stress of our modern lifestyle

Mounting evidence shows that physical activity, social interaction and sensorimotor stimulation provided by environmental enrichment (EE) exert several neurobehavioural effects traditionally interpreted as enhancements relative to standard housing (SH) conditions. However, this evidence rather indicates that SH induces many deficits, which could be ameliorated by exposing animals to an environment vaguely mimicking some features of their wild habitat. Rearing rodents in social isolation (SI) can aggravate such deficits, which can be restored by SH or EE. It is not surprising, therefore, that most preclinical stress models have included severe and unnatural stressors to produce a stress response prominent enough to be distinguishable from SH or SI-frequently used as control groups. Although current stress models induce a stress-related phenotype, they may fail to represent the stress of our urban lifestyle characterized by SI, poor housing and working environments, sedentarism, obesity and limited access to recreational activities and exercise. In the following review, we discuss the stress of living in urban areas and how exposures to and performing activities in green environments are stress relievers. Based on the commonalities between human and animal EE, we discuss how models of housing conditions (e.g., SI-SH-EE) could be adapted to study the stress of our modern lifestyle. The housing conditions model might be easy to implement and replicate leading to more translational results. It may also contribute to accomplishing some ethical commitments by promoting the refinement of procedures to model stress, diminishing animal suffering, enhancing animal welfare and eventually reducing the number of experimental animals needed.

Urban upbringing and psychotic experiences in the United States: A racial and geographic comparison

Urban upbringing has been associated with greater risk for psychotic experiences, though research is needed to confirm whether this is true in the U.S., and whether the association depends on race, type of experience, and region of the country. We analyzed data from the National Comorbidity Survey Replication (White respondents only) and the National Survey of American Life (Black respondents). Multivariable logistic regression models found that urban upbringing was not significantly associated with lifetime psychotic experiences for Whites, but was significantly associated with lower odds for Blacks, adjusting for socio-demographic covariates and common mental disorders. Rural upbringing was associated with greater odds of lifetime auditory hallucinatory experiences for Blacks. Exploratory analyses suggested growing up in a large city or 'other' environment were associated with greater odds of lifetime psychotic experiences among Whites currently residing in the Northeast, but lower odds among Whites residing in the South. For Blacks currently residing in the West, rural upbringing was associated with significantly greater odds of lifetime psychotic experiences when compared with growing up in a large city. White and Blacks may have different lived experiences in urban and rural settings, calling for more race- and location- specific research to explain these diverging patterns.

Is there a link between air pollution and mental disorders?

Several studies have demonstrated the association between air pollution and different medical conditions including respiratory and cardiovascular diseases. Air pollutants might have a role also in the etiology of mental disorders in the light of their toxicity on central nervous system. Purpose of the present manuscript was to review and summarize available data about an association between psychiatric disorders and air pollution. A research in the main database sources has been conducted to identify relevant papers about the topic. Different air pollutants and in particular PM and nitric oxides have been associated with poor mental health; long exposition to PM_2.5 has been associated with an increased risk of new onset of depressive symptoms (Cohen's effect size d: 0.05-0.81), while increased concentration of nitric dioxide in summer with worsening of existing depressive conditions (Cohen's effect size d: 0.05-1.77). However, the interpretation of these finding should take into account the retrospective design of most of studies, different periods of observations, confounding factors such as advanced age or medical comorbidity. Further studies with rigorous methodology are needed to confirm the results of available literature about this topic.

Association of Urbanicity With Psychosis in Low- and Middle-Income Countries

Importance

Urban residence is one of the most well-established risk factors for psychotic disorder, but most evidence comes from a small group of high-income countries.

Objective

To determine whether urban living is associated with greater odds for psychosis in low- and middle-income countries (LMICs).

Design, Setting, and Participants

This international population-based study used cross-sectional survey data collected as part of the World Health Organization (WHO) World Health Survey from May 2, 2002, through December 31, 2004. Participants included nationally representative general population probability samples of adults (≥18 years) residing in 42 LMICs (N = 215 682). Data were analyzed from November 20 through December 5, 2017.

Exposures

Urban vs nonurban residence, determined by the WHO based on national data.

Main Outcomes and Measures

Psychotic experiences, assessed using the WHO Composite International Diagnostic Interview psychosis screen, and self-reported lifetime history of a diagnosis of a psychotic disorder.

Results

Among the 215 682 participants (50.8% women and 49.2% men; mean [SD] age, 37.9 [15.7] years), urban residence was not associated with psychotic experiences (odds ratio [OR], 0.99; 95% CI, 0.89-1.11) or psychotic disorder (OR, 0.89; 95% CI, 0.76-1.06). Results of all pooled analyses and meta-analyses of within-country effects approached a null effect, with an overall OR of 0.97 (95% CI, 0.87-1.07), OR for low-income countries of 0.98 (95% CI, 0.82-1.15), and OR for middle-income countries of 0.96 (95% CI, 0.84-1.09) for psychotic experiences and an overall OR of 0.92 (95% CI, 0.73-1.16), OR for low-income countries of 0.92 (95% CI, 0.66-1.27), and OR for middle-income countries of 0.92 (95% CI, 0.67-1.27) for psychotic disorder.

Conclusions and Relevance

Our results provide evidence that urbanicity, a well-established risk factor for psychosis, may not be associated with elevated odds for psychosis in developing countries. This finding may provide better understanding of the mechanisms by which urban living may contribute to psychosis risk in high-income countries, because urban-rural patterns of cannabis use, racial discrimination, and socioeconomic disparities may vary between developing and developed nations.

Social determinants of mental disorders and the Sustainable Development Goals: a systematic review of reviews

Mental health has been included in the UN Sustainable Development Goals. However, uncertainty exists about the extent to which the major social determinants of mental disorders are addressed by these goals. The aim of this study was to develop a conceptual framework for the social determinants of mental disorders that is aligned with the Sustainable Development Goals, to use this framework to systematically review evidence regarding these social determinants, and to identify potential mechanisms and targets for interventions. We did a systematic review of reviews using a conceptual framework comprising demographic, economic, neighbourhood, environmental events, and social and culture domains. We included 289 articles in the final Review. This study sheds new light on how the Sustainable Development Goals are relevant for addressing the social determinants of mental disorders, and how these goals could be optimised to prevent mental disorders.

The role of genetic liability in the association of urbanicity at birth and during upbringing with schizophrenia in Denmark

BACKGROUND

Studies have indicated that the association of urbanicity at birth and during upbringing with schizophrenia may be driven by familial factors such as genetic liability. We used a population-based nested case-control study to assess whether polygenic risk score (PRS) for schizophrenia was associated with urbanicity at birth and at age 15, and to assess whether PRS and parental history of mental disorder together explained the association between urbanicity and schizophrenia.

METHODS

Data were drawn from Danish population registries. Cases born since 1981 and diagnosed with schizophrenia between 1994 and 2009 were matched to controls with the same sex and birthdate (1549 pairs). Genome-wide data were obtained from the Danish Neonatal Screening Biobank and PRSs were calculated based on results of a separate, large meta-analysis.

RESULTS

Those with higher PRS were more likely reside in the capital compared with rural areas at age 15 [odds ratio (OR) 1.19, 95% confidence interval (CI) 1.01-1.40], but not at birth (OR 1.09, 95% CI 0.95-1.26). Adjustment for PRS produced almost no change in relative risks of schizophrenia associated with urbanicity at birth, but slightly attenuated those for urban residence at age 15. Additional adjustment for parental history led to slight attenuation of relative risks for urbanicity at birth [incidence rate ratio (IRR) for birth in capital = 1.54, 95% CI 1.18-2.02; overall p = 0.016] and further attenuation of relative risks for urbanicity at age 15 (IRR for residence in capital = 1.32, 95% CI 0.97-1.78; overall p = 0.148).

CONCLUSIONS

While results regarding urbanicity during upbringing were somewhat equivocal, genetic liability as measured here does not appear to explain the association between urbanicity at birth and schizophrenia.

Associations between urban upbringing and cortical thickness and gyrification

Urbanicity has been linked to several psychiatric disorders, especially schizophrenia. Recent studies suggest effects of urban upbringing and stress on brain structure and function. Here, we used surface-based and voxel-based morphometry to study the effects of urban upbringing in different environments on variation in brain structure in a non-clinical sample. We recruited 85 young and healthy individuals from the community and recorded urban vs. rural background in their first 15 years of live. All participants underwent T1-weighted 3T MRI, which were then processed via CAT12 toolbox (in SPM12) to analyse cortical volume, thickness and gyrification. These parameters were correlated with an established measure of cumulative childhood and adolescence exposure to urban environments. We found significant (p < 0.05, FWE-corrected) negative correlations of cortical thickness with higher index of urban upbringing in the left dorsolateral prefrontal cortex, bilateral medial prefrontal cortices, as well as temporal cortices including the left superior temporal and left parahippocampal cortex. In contrast, results for volume and gyrification (incl. left posterior cingulate cortex) did not survive correction for multiple comparisons. We show a strong association of early-life urbanicity with cortical thickness in several areas, which are also impaired in schizophrenia patients. Along with other findings, these results converge on the dorsolateral prefrontal cortex as an area mediating this environmental risk.

Season of birth and schizophrenia: Evidence from China

Controversies exist whether season of birth is associated with schizophrenia development later in life, and evidence has mainly come from studies done in developed countries. This study examines the association between season of birth and risk for schizophrenia in China, with special attention to geographical region, urbanity, and gender. Using data from China's Second National Sampling Survey on Disability, a large-scale, nationally representative sample (N=2,052,694), this study employs discrete-time hazard models to compare the risk for schizophrenia development for people born in different seasons, and conducts subsample analyses by geographical region, urbanity, and gender. People born in the spring have the highest risk when compared to people born in the winter, summer or autumn. Furthermore, the relatively higher risk for people born in the spring is greater in the southern half of the country, in rural areas, and for women. The findings are consistent with results from a robustness check done among people who were conceived and born from 1955 to 1965, periods before, during, and after the 1959-1961 Chinese Famine. This study supports the presence of an association between season of birth and risk for schizophrenia development and of heterogeneity by geographical region, urbanity, and gender.

Environmental pollution and risk of psychotic disorders: A review of the science to date

Environmental pollution is a global problem with diverse and substantial public health implications. Although many environmental (i.e., non-genetic) risk factors for schizophrenia and other psychotic disorders have been identified, there has been comparatively little research on pollution as a possible risk factor. This is despite the fact that gene-by-environment interactions and epigenetic mechanisms are now recognized as likely facets of the etiology of schizophrenia, and the fact that pollution could potentially mediate the association between urban birth/upbringing and elevated risk. We conducted a review of the literature to date in order to summarize and synthesize work in this area. We identified 13 research reports and 16 review articles. Based on the extant knowledge in this area and what is known about the pathophysiology of schizophrenia, it is feasible that exposure to xenobiotic heavy metals such as lead and cadmium, constituents of air pollution such as particulate matter and nitrogen and sulfur oxides, organic solvents, and other constituents of environmental pollution could be component causes. Further research-from the cellular to epidemiological levels-is clearly needed. If causation is proven, enhancements of policy intended to reduce human exposure to environmental pollution could reduce the burden of schizophrenia and possibly other mental illnesses.

Epidemiology of depression with psychotic experiences and its association with chronic physical conditions in 47 low- and middle-income countries

BACKGROUND

The co-existence of depression and psychotic experiences (PEs) is associated with more pronounced adverse health outcomes compared to depression alone. However, data on its prevalence and correlates are lacking in the general adult population, and there is no published data on its association with chronic physical conditions.

METHOD

Cross-sectional, community-based data from 201 337 adults aged ⩾18 years from 47 low- and middle-income countries from the World Health Survey were analyzed. The presence of past 12-month PE and DSM-IV depression was assessed with the Composite International Diagnostic Interview (CIDI). Information on six chronic medical conditions (chronic back pain, edentulism, arthritis, angina, asthma, diabetes) were obtained by self-report. Multivariable logistic regression analysis was performed.

RESULTS

The crude overall prevalence of co-morbid depression/PEs was 2.5% [95% confidence interval (CI) 2.3-2.7%], with the age- and sex-adjusted prevalence ranging from 0.1% (Sri Lanka, Vietnam) to 9.03% (Brazil). Younger age, urban setting, current smoking, alcohol consumption, and anxiety were significant correlates of co-existing depression/PEs. Co-occurring depression/PEs was associated with significantly higher odds for arthritis, angina, and diabetes beyond that of depression alone after adjusting for sociodemographics, anxiety, and country, with odds ratios (depression/PEs v. depression only) being: arthritis 1.30 (95% CI 1.07-1.59, p = 0.0086); angina 1.40 (95% CI 1.18-1.67, p = 0.0002); diabetes 1.65 (95% CI 1.21-2.26, p = 0.0017).

CONCLUSIONS

The prevalence of co-existing depression/PEs was non-negligible in most countries. Our study suggests that when depression/PE or a chronic condition (e.g. arthritis, angina, diabetes) is detected, screening for the other may be important to improve clinical outcomes.

Unravelling psychosis: psychosocial epidemiology, mechanism, and meaning

This paper reviews a revolution in our understanding of psychosis over the last 20 years. To a major extent, this has resulted from a process of cross-fertilization between psychosocial epidemiology and cognitive behavior therapy for psychosis (CBT-p). This encouraged complementary strategies for the acquisition and analysis of data. These include the use of a range of dependent variables related to psychosis, and the exploitation of data from cross-sectional and longitudinal epidemiological surveys, virtual reality experiments, experience sampling methodology, and treatment trials. The key element is to investigate social and psychological measures in relation to each other. This research has confirmed the role of the external social world in the development and persistence of psychotic disorder. In addition, several psychological drivers of psychotic experiences have been identified. There is now persuasive evidence that the influence of social factors in psychosis is significantly mediated by non-psychotic symptoms, particularly mood symptoms and other attributes of affect such as insomnia. Psychotic symptoms are also driven by reasoning biases such as jumping to conclusions and belief inflexibility, though little is known about social influences on such biases. It is now clear that there are many routes to psychosis and that it takes many forms. Treatment of all kinds should take account of this: the dependence of CBT-p on a detailed initial formulation in terms of psychological processes and social influences is an example of the required flexibility. Individual mediators are now being targeted in specific forms of CBT-p, with good effect. This in turn corroborates the hypothesized role of non-psychotic symptoms in mediation, and attests to the power of the approaches described.