Current policy from the Department of Health advocates for an integrated approach to treating patients with a dual diagnosis. However, pragmatic and clinically effective brief interventions that can be delivered by nurses across mental health settings remain underdeveloped. Motivational interviewing has had some successful exposure in the field of dual diagnosis; however, harm reduction remains unexplored both conceptually and in terms of clinical intervention. This literature review examines the notion of harm reduction as a method of identifying and reducing the harm associated with the misuse of drugs and alcohol in relation to mental health problems. Currently there is a paucity of good quality evidence for integrated interventions in the treatment of dually diagnosed patients. Therefore, the papers are analysed in respect of their methodological quality and contribution to the evidence base to inform both future research and mental health nursing practice.