The practice study on outpatient psychotherapy in Switzerland (PAP-S) is one of the few studies that investigates treatment methods actually applied in psychiatric and psychotherapeutic care. This naturalistic study thus reflects a wide range of therapy methods currently approved in Switzerland, including approaches that have been less studied so far. The authors present the key findings of the study conducted from 2006 to 2013 on the effectiveness of various psychotherapy methods in the outpatient sector. Additionally, the results outline which factors influence therapy outcomes and to what extent representatives of different concepts or psychotherapy methods differ or resemble each other in terms of applied intervention techniques. It was also demonstrated that the influence of the schools.