AIMS AND OBJECTIVES: This paper aims to explore the effectiveness of the mental health nurse practitioner role in the emergency department in the context of the growing use of special units or segregated areas to manage particular kinds of mental health presentations, often complicated by substance use. BACKGROUND: In recent years, there has been a significant increase in mental health presentations to emergency departments, often complicated by substance abuse. Emergency departments have introduced a variety of mechanisms to address this growing problem. With the introduction of mental health nurse practitioners, opportunities arise to reconsider these mechanisms. DESIGN: Discursive paper. METHODS: In this discursive paper, contemporary practices are described in relation to 'special care areas', 'psychiatric emergency centres' and 'short-stay units'. The mental health nurse practitioner role in training and capacity building is also explored and the notion of 'locational processes' described. Rather than being presented as an alternative to short-stay units, the mental health nurse practitioner role is explored in its potential to enhance mental health nursing practice in a sometimes difficult clinical environment. RESULTS: The paper provides evidence from literature and practice that the clinical outcome for consumers is enhanced through the mental health nurse practitioner role. CONCLUSIONS: It is argued that the introduction of the mental health nurse practitioner role in the emergency department leads to increased staff competence and confidence in interacting with those presenting with mental health issues. The mental health nurse practitioner role also addresses the serious problem of stigma associated with those with a mental health issue. RELEVANCE TO CLINICAL PRACTICE: It is expected that those presenting with mental health issues to the emergency department will benefit through the increased assessment and management skills of staff.