Melike Karaçam Doğan

Grounded in dimensional and transdiagnostic frameworks, the work conceptualized both autism and psychosis as continuously distributed phenomena rather than discrete diagnostic categories, and adopted an exposome perspective to investigate how genetic, environmental, and psychological factors influence mental health outcomes. Chapter 2 investigated whether genetic liability for schizophrenia and established environmental risk factors moderate the association between autistic traits (ATs) and psychosis expression (PE). The findings demonstrated that childhood trauma (CT) strengthened the association between ATs and PE, whereas polygenic risk for schizophrenia and other environmental risk factors did not substantially modify this relationship. Analyses across psychosis subdomains (positive, negative, and depressive) showed that CT subtypes interacted with ATs on positive symptoms, while emotional abuse emerged as the only CT subtype that significantly strengthened the association of ATs with all psychosis domains.

Chapter 3 shifted the focus from risk to resilience by examining psychological protective mechanisms. It investigated whether coping strategies, extroverted personality traits, and perceived parenting quality buffered the association between ATs and PE. The results indicated that engagement coping styles (such as seeking social support and reassuring thoughts), extraversion, and optimal parenting attenuated this association, whereas disengagement coping strategies, including passive-reacting coping and avoidance, were associated with a stronger association.

Chapter 4 investigated sex differences in the associations between childhood adversity, coping strategies, and psychosis expression. Several shared and sex-specific patterns were identified. Emotional abuse emerged as a trans-syndromal risk factor in both sexes, while the association between physical neglect and PE was observed specifically in males. Passive-reacting coping was linked to higher levels of PE in both sexes. Among females, seeking social support, reassuring thoughts, and palliative-reacting coping were more strongly associated with lower symptom levels, whereas in males maladaptive coping patterns, such as avoidance, were associated with worse outcomes.

Chapter 5 investigated sex differences in the association between ATs and a broad range of psychopathological symptoms in the general population. Higher levels of ATs were associated with increased psychopathology domains in both sexes; however, the associations for depressive and obsessive–compulsive symptom domains were more pronounced in females.