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In Europe, the incidence of psychotic disorder is high in certain migrant and minority ethnic groups (hence: ‘minorities’). However, it is unknown how the incidence pattern for these groups varies within this continent. Our objective was to compare, across sites in France, Italy, Spain, the UK and the Netherlands, the incidence rates for minorities and the incidence rate ratios (IRRs, minorities v. the local reference population).
The European Network of National Schizophrenia Networks Studying Gene–Environment Interactions (EU-GEI) study was conducted between 2010 and 2015. We analyzed data on incident cases of non-organic psychosis (International Classification of Diseases, 10th edition, codes F20–F33) from 13 sites.
The standardized incidence rates for minorities, combined into one category, varied from 12.2 in Valencia to 82.5 per 100 000 in Paris. These rates were generally high at sites with high rates for the reference population, and low at sites with low rates for the reference population. IRRs for minorities (combined into one category) varied from 0.70 (95% CI 0.32–1.53) in Valencia to 2.47 (95% CI 1.66–3.69) in Paris (test for interaction: p = 0.031). At most sites, IRRs were higher for persons from non-Western countries than for those from Western countries, with the highest IRRs for individuals from sub-Saharan Africa (adjusted IRR = 3.23, 95% CI 2.66–3.93).
Incidence rates vary by region of origin, region of destination and their combination. This suggests that they are strongly influenced by the social context.
Hydrogen lithography has been used to template phosphine-based surface chemistry to fabricate atomic-scale devices, a process we abbreviate as atomic precision advanced manufacturing (APAM). Here, we use mid-infrared variable angle spectroscopic ellipsometry (IR-VASE) to characterize single-nanometer thickness phosphorus dopant layers (δ-layers) in silicon made using APAM compatible processes. A large Drude response is directly attributable to the δ-layer and can be used for nondestructive monitoring of the condition of the APAM layer when integrating additional processing steps. The carrier density and mobility extracted from our room temperature IR-VASE measurements are consistent with cryogenic magneto-transport measurements, showing that APAM δ-layers function at room temperature. Finally, the permittivity extracted from these measurements shows that the doping in the APAM δ-layers is so large that their low-frequency in-plane response is reminiscent of a silicide. However, there is no indication of a plasma resonance, likely due to reduced dimensionality and/or low scattering lifetime.
Microvascular health is a main determinant of coronary blood flow reserve and myocardial vascular resistance. Extracardiac capillary abnormality has been reported in subjects at increased coronary heart disease risk, such as prehypertension, hypertension, diabetes, hyperlipidemia, and atherosclerosis. We have reported cardiovascular dysfunction in a cohort of maternal nutrient reduction (MNR)-induced intrauterine growth restriction (IUGR) baboon offspring. Here we test the hypothesis that there is oral capillary rarefaction associated with MNR-induced IUGR. Capillary density was quantified using in vivo high-power capillaroscopy on seven middle-aged (~10.7 yr; human equivalent ~40 yr) male IUGR baboons and seven male age-matched controls in the lateral buccal and inferior labial mucosa. While no difference was found between groups in either area by fraction area or optical density for these vascular beds derived from fetal preductal vessels, further studies are needed on post-ductal vascular beds, retina, and function.
First episode psychosis (FEP) patients who use cannabis experience more frequent psychotic and euphoric intoxication experiences compared to controls. It is not clear whether this is consequent to patients being more vulnerable to the effects of cannabis use or to their heavier pattern of use. We aimed to determine whether extent of use predicted psychotic-like and euphoric intoxication experiences in patients and controls and whether this differs between groups.
We analysed data on patients who had ever used cannabis (n = 655) and controls who had ever used cannabis (n = 654) across 15 sites from six countries in the EU-GEI study (2010–2015). We used multiple regression to model predictors of cannabis-induced experiences and to determine if there was an interaction between caseness and extent of use.
Caseness, frequency of cannabis use and money spent on cannabis predicted psychotic-like and euphoric experiences (p ⩽ 0.001). For psychotic-like experiences (PEs) there was a significant interaction for caseness × frequency of use (p < 0.001) and caseness × money spent on cannabis (p = 0.001) such that FEP patients had increased experiences at increased levels of use compared to controls. There was no significant interaction for euphoric experiences (p > 0.5).
FEP patients are particularly sensitive to increased psychotic-like, but not euphoric experiences, at higher levels of cannabis use compared to controls. This suggests a specific psychotomimetic response in FEP patients related to heavy cannabis use. Clinicians should enquire regarding cannabis related PEs and advise that lower levels of cannabis use are associated with less frequent PEs.
The ‘jumping to conclusions’ (JTC) bias is associated with both psychosis and general cognition but their relationship is unclear. In this study, we set out to clarify the relationship between the JTC bias, IQ, psychosis and polygenic liability to schizophrenia and IQ.
A total of 817 first episode psychosis patients and 1294 population-based controls completed assessments of general intelligence (IQ), and JTC, and provided blood or saliva samples from which we extracted DNA and computed polygenic risk scores for IQ and schizophrenia.
The estimated proportion of the total effect of case/control differences on JTC mediated by IQ was 79%. Schizophrenia polygenic risk score was non-significantly associated with a higher number of beads drawn (B = 0.47, 95% CI −0.21 to 1.16, p = 0.17); whereas IQ PRS (B = 0.51, 95% CI 0.25–0.76, p < 0.001) significantly predicted the number of beads drawn, and was thus associated with reduced JTC bias. The JTC was more strongly associated with the higher level of psychotic-like experiences (PLEs) in controls, including after controlling for IQ (B = −1.7, 95% CI −2.8 to −0.5, p = 0.006), but did not relate to delusions in patients.
Our findings suggest that the JTC reasoning bias in psychosis might not be a specific cognitive deficit but rather a manifestation or consequence, of general cognitive impairment. Whereas, in the general population, the JTC bias is related to PLEs, independent of IQ. The work has the potential to inform interventions targeting cognitive biases in early psychosis.
Daily use of high-potency cannabis has been reported to carry a high risk for developing a psychotic disorder. However, the evidence is mixed on whether any pattern of cannabis use is associated with a particular symptomatology in first-episode psychosis (FEP) patients.
We analysed data from 901 FEP patients and 1235 controls recruited across six countries, as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. We used item response modelling to estimate two bifactor models, which included general and specific dimensions of psychotic symptoms in patients and psychotic experiences in controls. The associations between these dimensions and cannabis use were evaluated using linear mixed-effects models analyses.
In patients, there was a linear relationship between the positive symptom dimension and the extent of lifetime exposure to cannabis, with daily users of high-potency cannabis having the highest score (B = 0.35; 95% CI 0.14–0.56). Moreover, negative symptoms were more common among patients who never used cannabis compared with those with any pattern of use (B = −0.22; 95% CI −0.37 to −0.07). In controls, psychotic experiences were associated with current use of cannabis but not with the extent of lifetime use. Neither patients nor controls presented differences in depressive dimension related to cannabis use.
Our findings provide the first large-scale evidence that FEP patients with a history of daily use of high-potency cannabis present with more positive and less negative symptoms, compared with those who never used cannabis or used low-potency types.
Ethnic minority groups in Western countries face an increased risk of psychotic disorders. Causes of this long-standing public health inequality remain poorly understood. We investigated whether social disadvantage, linguistic distance and discrimination contributed to these patterns.
We used case–control data from the EUropean network of national schizophrenia networks studying Gene-Environment Interactions (EU-GEI) study, carried out in 16 centres in six countries. We recruited 1130 cases and 1497 population-based controls. Our main outcome measure was first-episode ICD-10 psychotic disorder (F20–F33), and exposures were ethnicity (white majority, black, mixed, Asian, North-African, white minority and other), generational status, social disadvantage, linguistic distance and discrimination. Age, sex, paternal age, cannabis use, childhood trauma and parental history of psychosis were included as a priori confounders. Exposures and confounders were added sequentially to multivariable logistic models, following multiple imputation for missing data.
Participants from any ethnic minority background had crude excess odds of psychosis [odds ratio (OR) 2.03, 95% confidence interval (CI) 1.69–2.43], which remained after adjustment for confounders (OR 1.61, 95% CI 1.31–1.98). This was progressively attenuated following further adjustment for social disadvantage (OR 1.52, 95% CI 1.22–1.89) and linguistic distance (OR 1.22, 95% CI 0.95–1.57), a pattern mirrored in several specific ethnic groups. Linguistic distance and social disadvantage had stronger effects for first- and later-generation groups, respectively.
Social disadvantage and linguistic distance, two potential markers of sociocultural exclusion, were associated with increased odds of psychotic disorder, and adjusting for these led to equivocal risk between several ethnic minority groups and the white majority.
Chapter 2 places the movement of 99,752 recaptives within a broader history of forced migration in the Atlantic world, conceptualizing the voyages of Liberated Africans as a “structuring link” between homeland and diaspora. The chapter shifts the level analysis away from aggregate origins to the individual experiences of Africans, whom the 1807 Abolition Act and the deployment of the Anti-Slavery Squadron were intended to help. To do so I draw on a corpus of narratives composed in Sierra Leone that comprise some of the few first-hand accounts we have of enslavement in Africa. I also introduce the argument, further elaborated on in subsequent chapters, that this experience was a crucible during which “shipmates” forged deep, lasting connections. Nineteenth-century Sierra Leone was populated first and foremost by the arrival of some five hundred cohorts of shipmates. The Middle Passage experienced by recaptives was both an ending – to family, to friends, to familiar sights and sounds – but also a beginning, to new communities, families, and affinities that helped define colonial society in Sierra Leone.
The concluding chapter follows the buildup, instigation, suppression, and legacies of the Cobolo War, an 1832 conflagration that marked the largest flashpoint between Liberated Africans and the colonial state. During the war, a group of “Mahomedan Aku” (Yoruba Muslim) Liberated Africans, who had previously vacated the colony temporarily, defeated a colonial militia instructed to bring the fugitives back to Freetown. The actions of these Aku Liberated Africans were contemporaneous with a pattern of violent resistance to colonial oppression instigated by Yoruba speakers around the Atlantic world in the 1820s and 1830s. Although eventually defeated, the conflict at Cobolo had long-standing legacies. In the months and years after the battle – and a failed attempt to try the leaders for treason – British officials embarked on a campaign of intimidation and repression, toppling mosques that Muslim Liberated Africans had built as they moved into communities to ensure their religious autonomy. This chapter traces the relationship between Muslim and ethnic identity in the context of colonial oppression, the role of Islam in shaping the conceptual meaning of “Aku,” and the endurance of Muslim Liberated African communities over subsequent generations of Sierra Leonean history.
The conclusion moves chronologically forward, exploring the connections that the colony-born offspring of Liberated Africans felt toward their parents’ societies of birth, their forms of communal association, and their cultural and religious practices. While the emphasis of the study is on the charter generation who experienced the Middle Passage, themes such as community and identity do not lend them well to concrete end dates. The conclusion argues not only that certain customs and forms of communal identification “survived” the westernizing and Christianizing influences of colonial life, but that the late nineteenth century saw a resurgence or revival of such customs and associations. At a time when disillusionment with the British colonial project was at its height, the second- and third-generation offspring of those who came to Freetown on slave ships looked once again to the languages, dress, and community organizations of their forebears. This Conclusion argues that processes of ethnogenesis and creolization cannot simply be seen as a linear process in which certain vestiges can be traced across generations to certain regions of the African continent.
The penultimate chapter broaches the question of why, given the multifarious origins of Liberated Africans, a single recaptive nation – the Aku – came to dominate colonial and missionary discourse on recaptives, as well as most subsequent historical accounts of Liberated African society. Most studies of Sierra Leone have asserted that “Aku” was a colonial term for Yoruba peoples from present-day Nigeria and have echoed contemporary observations that they were the largest and “most cohesive” group within Sierra Leonean society. This chapter considers the role of language in shaping Aku identity, and the interaction between Islam, Christianity, and “traditional” oriṣa worship in defining the Aku. It then traces the shifting relationship between diaspora and homeland, as Aku merchants and missionaries returned to coastal towns near their ancestral homes after 1838, bringing with them a more encompassing sense of Yoruba ethnicity. This chapter argues that what it meant to be Aku in Sierra Leone and what it meant to be Yoruba in Yorubaland were defined and reinforced through a dialogue along the Atlantic coast of West Africa. In doing so it advocates for a nonlinear conception of diaspora that applies not only to the Americas but to diasporas within the African continent.
While the first three chapters explore the regional origins of Liberated Africans and the experiences of their forced migrations to Sierra Leone, the later chapters explore the new communities and identities these migrants forged. Chapter 4 investigates the multifarious “nations” that were at the center of Liberated African identity formation and political life. Within Liberated African society, Africans formed communities based on common language and experience, referred to in colonial and missionary documents as nations. The chapter explores how the most prominent of these nations – the Aku, Igbo, Popo, Hausa. Cosso, Moko, Congo, and Calabar – were diasporic creations whose members congregated based on similar language and place of origin. It looks at the varying meanings of these “national” categories from the perspectives of Liberated Africans, missionaries, and colonial officials. The chapter’s discussion fits within larger debates over the meaning of ethnicity in colonial Africa and the diaspora and how identity was shaped by particular imperial contexts.