The concept of best treatment practice is a response to the growing diversity of therapeutic experience and to the frequently inadequacy of service reality and guidelines. Ideally, best practice guidelines are based on the available research evidence about effi cacy and effectiveness of therapeutic approaches. But limitations of outcome research must be taken into consideration as well as limitations of guideline applicability. Circumstantial factors are also relevant for treatment outcomes, and clinicians are expected to adapt evidence-based recommendations to such factors in their daily practice with individual patients. In addition, availability and access to recommended treatments are in the responsibility of service planners and providers, thereby facilitating the implementation of best practices. We understand best practice not as treatment provided in some centres of excellence, but as a system providing all those in need of treatment in the best possible way. Finally, major changes are expected for the future, redirecting the focus from a traditional evaluation of clinical usefulness for populations to an assessment of individually optimised interventions (personalised medicine: 'treating the patient, not the disease').