Psychiatric Advance Directives (PADs) are tools that allow service users to state their treatment preferences for mental health crises in advance. In this chapter, we give an overview of the ethical case for psychiatric advance directives and similar documents as well as the empirical literature on their practical implementation. We first introduce different types of PADs and point out differences with respect to their legal status and purpose. We summarize which preferences are typically contained in PADs and explain how PADs can enhance service users’ autonomy from an ethical perspective. The chapter then provides an overview of outcomes of the application of PADs in practice, including use of detention in psychiatric inpatient settings, adverse consequences of relapse, therapeutic alliance and perceived self-determination. Finally, we point out barriers to the application of PADs and discuss different strategies to improve their implementation in clinical practice.