Spezifische Aspekte tagesklinisch-psychiatrischer Versorgung am Beispiel der Dialektisch-Behavioralen Therapie (DBT) und der Akzeptanz- und Commitment-Therapie (ACT)

This habilitation thesis focuses on specific questions within psychiatric health services research, particularly regarding day clinic treatment offerings. It begins with the first survey conducted in the German-speaking world on disorder-specific, day clinic, and inpatient treatment options for individuals with borderline personality disorder (BPD). The findings reveal a significant undersupply of care, characterized by long waiting times and a very high patient-to-treatment-place ratio for DBT (Dialectical Behavior Therapy), clearly indicating that existing services do not meet actual demand. Building on this, a specialized DBT day clinic in a Berlin psychiatric care region was evaluated. This clinic aimed to address the identified treatment gap. The evaluation showed, for the first time, statistically significant to highly significant improvements in BPD-specific symptoms. The study also systematically examined negative effects of the DBT treatment – a first for a day clinic setting – by identifying which negative effects patients subjectively experienced. Additionally, the research sought to identify patient-level predictors for poor treatment response, with the goal of informing future therapeutic developments for BPD. Subsequent publications stemmed from this methodological evaluation approach, now applied to a different therapeutic concept: a transdiagnostic (i.e., not disorder-specific) treatment in a day clinic for a more heterogeneous psychiatric patient group. These studies also demonstrated high treatment effectiveness, not only in symptom reduction but also in improvements in patients’ subjective quality of life. Notably, the negative effects of the transdiagnostic ACT (Acceptance and Commitment Therapy) approach were found to be lower compared to other clinical populations. The ACT day clinic study was conducted during the COVID-19 pandemic, thus reflecting the challenges of delivering mental health care during a particularly vulnerable period. In summary, the thesis examines the real-world implementation of psychiatric care structures from a health services research perspective, with a focus on day clinics. It scientifically documents the benefits and possible downsides of selected therapeutic methods and their sometimes surprising treatment outcomes. The findings are based on real, unfiltered data from two Berlin psychiatric care regions and provide a representative snapshot of mental health service delivery at the time of study. These results may contribute to the ongoing development of day clinic models to improve mental health care delivery. The two day clinics investigated serve as examples of different models within the evolving landscape of psychiatric care: one being a highly specialized, disorder-specific DBT program, the other a broad, transdiagnostic ACT approach. Both reflect recent trends toward more outpatient-oriented treatment structures in psychiatry.