Adverse life experiences and psychopathology trajectories in routine Cognitive Behaviour Therapy.

Background: Cognitive Behaviour Therapy (CBT) is an effective treatment for common mental disorders, yet individual outcomes vary. Adverse life experiences (ALEs), especially childhood trauma, are often linked to greater symptom severity and poorer treatment response, but their role in routine CBT remains unclear.Objective: To examine how ALEs relate to treatment trajectories in routine CBT and whether therapists' intervention choices are related to outcome differences.Method: Routine clinical data from a prospective observational cohort of 302 outpatients receiving CBT for depression or anxiety in Germany were analysed. ALEs were assessed with the Childhood Trauma Questionnaire (CTQ) and Life Events Checklist for DSM-5 (LEC-5). Global psychopathology was repeatedly measured with the Brief Symptom Checklist (BSCL), and therapists documented intervention use. We analysed the relationship between the CTQ and LEC-5 scores, intervention use, and BSCL trajectories.Results: Interpersonal ALEs predicted higher baseline symptom levels but were unrelated to intervention use. Unexpectedly, greater childhood trauma was associated with stronger symptom reduction over time, regardless of the applied interventions.Conclusions: Despite higher initial symptom burden, trauma-exposed patients showed substantial symptom reductions during routine CBT. Future research should clarify the therapeutic processes associated with these trajectories.