There is undoubtedly a complex association between early life factors and schizotypal personality disorder (SPD) which represents as schizotypal symptoms in the adolescent population. To explore this relationship, this dissertation first starts with a systematic review of early life factors related to schizotypal symptoms. Twenty-four studies were identified following the PRISMA guideline. Three important clusters of early life factors found to be associated with schizotypal symptoms: prenatal and early postnatal factors, childhood trauma, and parental factors. Standardized measurement tools and well-designed longitudinal studies are needed to validate the associations between specific types or cumulative effects of early life factors and SPD. In addition, more research on the underlying mechanism connecting early life factors and SPD are needed. Then, this dissertation utilized the Philadelphia Neurodevelopmental Cohort dataset to first examine the association between different types and cumulative traumatic stressful events (TSEs, the most studied early life factors) and schizotypal symptoms in longitudinal community-based US adolescents. More than half of the adolescents reported a childhood TSE. Significant effects were found for the specific TSE types on the three dimensions of schizotypal symptoms while controlling demographic and family history factors. However, no significant effects remained after further controlling for the symptomatic factors (i.e., psychosis spectrum symptoms, mood disorder, anxiety disorder, and behavior disorder). A dose-response effect of cumulative TSEs on cognitive-perceptual symptoms was significant after further controlling for symptomatic factors. Finally, the mediation effects of executive function (EF) and social cognition (SC) were further explored in the association between cumulative TSEs and dimensional schizotypal symptoms. Only significant mediation effect of TSEs on cognitive-perceptual symptoms through executive function was found when adjusting for the demographic factors and family history factors. The dissertation findings call for more research to determine the roles of early life factors play in the development of SPD. It is important to consider confounds when examining associations between TSEs and schizotypal symptoms. Trauma-informed care to consider universal screenings of trauma in primary care may be particularly important. As executive function improvement program should be incorporated into interventions to reduce the burden of schizotypal symptoms in the adolescent population.