Objective:Psychotic-like experiences (PLEs) often occur across different non-psychotic disorders in adolescent and young adult population and are related to early trauma. However, the mechanisms of how exposure to early trauma shapes the risk of PLEs are unclear. In our study, we investigated whether borderline personality features and further non-psychotic symptoms, i.e. factors related to both PLEs and childhood trauma, may mediate the relationship between childhood trauma and PLEs.Methods:Two hundred inpatients aged 16–21 years who were treated due to non-psychotic disorders were included. PLEs were assessed with the Prodromal Questionnaire (PQ-16). Childhood Trauma was assessed with the Adverse Childhood Experience Questionnaire (ACE). Borderline personality features were assessed by using the Borderline-Symptom Checklist (BSL-23). Presence and frequency of depressive symptoms and anxiety were assessed by Patient Health Questionnaire (PHQ-9) and Generalized Anxiety Disorder Questionnaire (GAD-7).Table 1Clinical characteristics (n = 200).Mean (SD)Male/female67/133Age18.72 (1.85)Clinical diagnosisDepressive disorder (F32.1, F32.2, F33.0, F33.1, F33.2)167 (83.5%)Anxiety disorder (F40.1, F41.0, F41.1, F41.2)51 (25.5%)ComorbiditiesPTSD26 (13.0%)Personality disorders (F60.30, F60.31, F60.4, F60.6, F60.7, F60.8, F61)124 (66.5%)Eating disorder (F50.0, F50.1, F50.2)19 (9.5%)Others (F42.1, F42.2, F45.1, F44.5, F90.0)33 (16.5%)Measures: The Structured Clinical Interview for the Diagnostic and statistical manual of mental disorders, 4th edition (DSM-IV) (SCID-I) and the Structured Clinical Interview for DSM-IV Axis II Personality Disorders II (SCID-II) were used to identify the clinical diagnoses.Results:A significant relationship between childhood trauma (ACE total score) and PLEs was found (ß = 0.30, 95% CI 0.247--0.659). In particular, emotional neglect (r = 0.298, p < 0.001) and sexual abuse (r = 0.264, p < 0.001) were significantly associated with PLEs. Borderline personality features fully mediated the relationship of childhood trauma and PLEs (ß = 0.12, 95% CI: -0.019--0.370). Anxiety and Depression showed a significant, but partial mediation of the relationship.Conclusion:Borderline personality features seem to be an important mediator of the relationship between childhood trauma and PLEs in adolescent patients with different non-psychotic psychiatric disorders. Theoretical and clinical implications are discussed.