Ergen ve genç erişkin nüfusta çevresel risk faktörlerin çalışma belleği sırasındaki nöral aktivasyon ve dinlenim halindeki fonksiyonel bağlantı üzerindeki etkisi ile psikoz eğilimine ilişkin etkileri

Experiencing symptoms of psychosis, such as delusions and hallucinations, is sometimes observed in the general, nonclinical populations in a mild form, and is often termed psychosis proneness (PP), potentially as part of the psychosis continuum. Understanding the neural, environmental and cognitive factors contributing to PP in young individuals during critical developmental periods remains unclear. Environmental risk correlations, causal factors, and neural correlates of psychosis proneness were investigated using fMRI during both task performance and resting state. To this end, three different studies were conducted. The first study examined the relationship between environmental risk factors including ethnic minority or migration history, obstetric complications, paternal age, urbanicity, trauma, cannabis use, and psychosis proneness and schizotypy using multilevel mixed effects linear regression. Additionally, schemas about the self and others were used to predict psychosis proneness and schizotypy, alongside an exploration of its neural correlates during working memory performance. In the second study, we used a data-driven approach, causal discovery analysis (CDA), a novel machine learning algorithm, to explore directional relationships among variables. The analysis identified negative self-schema as having the largest causal effect on psychosis proneness among all assessments. Furthermore, experiencing low levels of social cohesion and trust had a causal effect on psychosis proneness. Although our analysis could not exclude the possibility that other unmeasured factors may confound these relationships, the effect sizes (ES) were substantial: negative self-schema & PPS (ES= 0.54) and social cohesion and trust & PPS (ES= -0.18). Moreover, PPS was identified as a direct cause of increased activation in the dorsolateral prefrontal cortex (DLPFC) during working memory (ES= 0.12). CDA provided simultaneous directionality for 37 variables measured in the same individuals. Finally, in the third study, we applied CDA to a dataset that included resting-state fMRI functional connectivity (FC) indices, with two different configurations of prior knowledge. Negative self-schema and social cohesion & trust again emerged as a direct causal factor for psychosis proneness. However, psychosis proneness did not appear to influence mean FC indices during rest. Instead, it directly affected individual FC indices within the dorsal attention network. These findings highlight the significance of negative self-schema and social cohesion and trust in the general population with psychosis proneness, suggesting potential preventive interventions targeting these factors. Furthermore, the results highlight the roles of the DLPFC during working memory and the dorsal attention network during rest as a potential targets for understanding and addressing psychosis proneness. These findings represent the first data-driven analysis modelling causal mechanisms underlying psychosis proneness in the general population and further support the hypothesis of continuum of psychosis.