Impact of urban birth and upbringing on expression of psychosis in a Chinese undergraduate population

Background Urban birth and upbringing show consistent associations with psychotic illness but the key urban exposures remain unknown. Associations with psychotic-like experiences (PEs) are inconsistent. These could be confounded by common mental disorders associated with PEs. Furthermore, associations between PEs and urban exposures may not extrapolate to psychotic disorders such as schizophrenia. Methods Annual cross-sectional surveys among first year Chinese undergraduates 2014–2019 (n = 47,004). Self-reported, hierarchical categorisation of psychosis: from psychoticism, paranoid ideation, schizotypal symptoms, nuclear syndrome using SCL-90-R, to clinical diagnosis of schizophrenia. Depressive symptoms using PHQ 9. Dissociative symptoms and posttraumatic stress disorder (PTSD) measured using PCL-C. Etiological factors of family history and childhood disadvantage. We studied effects of urban birth, urban living and critical times of exposure in childhood on psychosis phenotypes. Results Associations with urbanicity were found only after adjustments for depression. Urban birth was associated with paranoia (AOR 1.34, 1.18–1.53), schizotypal symptoms (AOR 1.59, 1.29–1.96), and schizophrenia (AOR 2.07, 1.10–3.87). The same phenotypes showed associations with urban residence > 10 years. Only schizophrenia showed an association with urban exposure birth-3 years (AOR 7.01, 1.90–25.86). Child maltreatment was associated with both psychosis and depression. Urbanicity measured across the total sample did not show any associations with demography, family history of psychosis, or child maltreatment. Sensitivity analysis additionally adjusting for dissociative symptoms and PTSD showed the same pattern of findings. Conclusions Urban birth and urban living showed a hierarchical pattern of increasing associations from paranoid ideation to schizotypal disorder to schizophrenia, confirming that associations for psychotic experiences could be extrapolated to schizophrenia, but only after adjusting for confounding from depression, dissociative symptoms and PTSD. Several etiological factors were the same for psychosis and depression. Future studies of PEs should adjust for confounding from common mental disorders and dissociative symptoms. Effects of urbanicity on psychosis were not explained by demography, family history of mental disorder, or child maltreatment.

MMN amplitude in first-degree relatives of psychotic disorders: Links with cognition and schizotypy

Background: Mismatch negativity (MMN) amplitude is reliably reduced in psychotic disorders. While several studies have examined this effect in first-degree relatives of individuals with schizophrenia, few have sought to quantify deficits in relatives of individuals with other psychotic disorders. While some studies conclude that, compared to healthy subjects, first-degree relatives of schizophrenia show reduced MMN, others contradict this finding, a discrepancy which extends to two recent meta-analyses. Furthermore, though MMN is often shown to be associated with cognitive impairments and clinical symptoms in psychotic disorders, to our knowledge no studies have sought to examine these relationships in studies of first-degree relatives. Method: The present study sought to clarify the extent of MMN amplitude reductions in a large sample of siblings of individuals with diverse psychotic disorders (n=65), compared to cases with psychosis (n=220) and never psychotic comparison subjects (n=252). We further examined associations of MMN amplitude with cognition and schizotypal symptoms across these groups. Results: We found that MMN amplitude was intact in siblings compared to cases with psychosis. MMN amplitude was associated with cognition and schizotypal symptoms dimensionally across levels of familial risk. Conclusions: The present results imply that MMN amplitude reductions emerge as a result of, or in conjunction with, clinical features associated with psychosis. Such findings carry important implications for the utility of MMN amplitude as an indicator of inherited risk, and suggest that this component may be best conceptualized as a marker for clinical symptoms and cognitive impairments, rather than risk for psychosis per se.

Semantic priming and schizotypal personality: reassessing the link between thought disorder and enhanced spreading of semantic activation

The term schizotypy refers to a group of stable personality traits with attributes similar to symptoms of schizophrenia, usually classified in terms of positive, negative or cognitive disorganization symptoms. The observation of increased spreading of semantic activation in individuals with schizotypal traits has led to the hypothesis that thought disorder, one of the characteristics of cognitive disorganization, stems from semantic disturbances. Nevertheless, it is still not clear under which specific circumstances (i.e., automatic or controlled processing, direct or indirect semantic relation) schizotypy affects semantic priming or whether it does affect it at all. We conducted two semantic priming studies with volunteers varying in schizotypy, one with directly related prime-target pairs and another with indirectly related pairs. Our participants completed a lexical decision task with related and unrelated pairs presented at short (250 ms) and long (750 ms) stimulus onset asynchronies (SOAs). Then, they responded to the brief versions of the Schizotypal Personality Questionnaire and the Oxford-Liverpool Inventory of Feelings and Experiences, both of which include measures of cognitive disorganization. Bayesian mixed-effects models indicated expected effects of SOA and semantic relatedness, as well as an interaction between relatedness and directness (greater priming effects for directly related pairs). Even though our analyses demonstrated good sensitivity, we observed no influence of cognitive disorganization over semantic priming. Our study provides no compelling evidence that schizotypal symptoms, specifically those associated with the cognitive disorganization dimension, are rooted in an increased spreading of semantic activation in priming tasks.

M132. URBANICITY AND PSYCHOSIS IN A CHINESE UNDERGRADUATE POPULATION: PRELIMINARY FINDINGS

Background Urban birth and upbringing are consistently associated with schizophrenia and other psychoses but the key urban exposures remain unknown. China has previously found prevalence of psychosis higher in rural areas but has shown the largest displacement of population from rural into urban areas of any country in the world over the past 40 years. Studies of psychotic experiences (PE) show inconsistency but this may be due to confounding of PEs by depressive symptoms. This suggests the need to differentiate between PEs on a population continuum with non-affective psychosis and those secondary to common mental disorders when studying urbanicity. Our aims were to investigate effects of exposure to urban birth and upbringing on psychosis in a large Chinese undergraduate sample. Methods Cross-sectional surveys conducted annually during first year of university, 2014–2018, n=39,446. Self-reported categorical measures of psychosis included psychoticism, paranoid ideation, and schizotypal symptoms using SCL-90-R, and lifetime clinical diagnosis of schizophrenia; depressive symptoms using PHQ 9; putative etiological risk factors of family history and childhood maltreatment; urbanicity measured according to birth place in a major city (level 5 of a 5-level rural-urban scale), length of residence in urban location, and length of residence during three critical 5 year periods, birth - 15 years. We studied effects on our 4 psychosis phenotypes of (i) urban birth, (ii) urban living, (iii) critical times of exposure to urban environment, (iv) putative etiological risk factors, before and after adjusting for depression. We investigated associations between etiological risk factors and urban exposures. Results We identified 2,143 (5.4%) participants above a determined cut-off for psychoticism, 2,081 (5.3%) for paranoia, 760 (1.9%)with schizotypal symptoms, and 53 (0.1%) with schizophrenia. Effects of urban exposure on our psychosis phenotypes were only revealed following adjustments for depression in our models: Urban birth was associated with Paranoia (1.46, 1.24–1.70), schizotypal symptoms (1.90,1.48-2.42), and schizophrenia (2.30, 1.14–4.63), but not psychoticism. All four phenotypes were associated with 10–15 years of exposure to urban living, but not shorter periods. Only schizophrenia was associated with critical timings of total exposures of 1–3 years and 4–5 years during the first 5 years of life to an urban environment. There were no associations or negative associations between putative etiological factors and urban exposures. Discussion We confirmed that urban birth and living were associated with PEs and schizophrenia in this large sample of Chinese university students, but these findings only emerged after adjusting for depression. Depression is more prevalent in rural Chinese samples and previous studies may have been confounded by effects of PEs secondary to depression. There was a gradient of association between paranoia, schizotypal symptoms and schizophrenia, the latter showing strongest effects in association with urban exposures of birth and length of time in an urban environment. Only schizophrenia showed effects of critical timing of exposure to urban environment during infancy. Finally, we could not identify what exposures in the urban environment contributed to psychosis in our sample - although we could identify the etiological factors that did not. Among Sichuan students, there was no indication that urban effects were due to increased risk from demographic factors of male sex, lower family income, increased genetic risk, or child maltreatment, although these factors showed some effects on psychosis across the entire sample which included previous rural residents.

Schizotypal Traits and the Dark Triad From an Ecological Perspective: A Nonclinical Sample Study

The Dark Triad is a collection of socially aversive personality traits, namely subclinical psychopathy, Machiavellianism, and subclinical narcissism. These deviant traits, however, contribute to the success of individuals with dark personality traits. Therefore, Dark Triad traits can be conceived as pseudopathologies. Schizotypal traits have also been studies from the perspective of behavioral adaptations. In this study, we investigated whether schizotypal traits were associated with the Dark Triad traits and how schizotypal symptoms can be considered as parts of dark interpersonal strategies that contribute to the individual success of people with dark personality traits. A sample of 277 university students (198 females and 79 males; Mage = 20.64; SDage = 2.15) were recruited to fill out the Short Dark Triad and the Schizotypal Personality Questionnaire-Brief Revised. Statistical analyses revealed that Machiavellianism was positively associated with restricted emotional and social life. Narcissism was negatively associated with interpersonal problems. Psychopathy was positively associated with distorted perceptions/cognitions and disorganization. Results of the study are discussed within a behavioral ecology framework. This perspective emphasizes the adaptive values connected to schizotypal personality traits. We further discuss how these adaptive traits fit into strategies of individuals with Dark Triad traits, and how these schizotypal traits might restrict or further promote their individual success.