Received: 11 October 2020 Revised: 17 November 2020 Accepted: 21 November 2020 DOI: 10.1111/2047-3095.12309 ORIGINAL ARTICLE The Core Nursing Interventions in Adult Psychiatric Outpatient Care Identified by Nurses, a Delphi Study Maria Ameel M.Soc 1 Theo van Achterberg PhD 2 Ulla-Mari Kinnunen PhD 3 Raija Kontio PhD 1 Kristiina Junttila PhD 1 1 Helsinki University Hospital, Helsinki University, Helsinki, Finland and University of Turku department of Nursing Science, Turku, Finland 2 Leuven, Department of Public Health and Primary Care, Academic Centre for Nursing and Midwifery, Leuven, Belgium 3 University of Eastern-Finland, Faculty of Social Sciences and Business Studies, Department of Health and Social Management, Kuopio, Finland Author contact: makaam@utu.fi, with a copy to the Editor: journal@nanda.org Abstract Purpose: To define the core nursing interventions identified by nurses in the adult psychi- atric outpatient care setting. Methods: A two-round Delphi study. The panel consisted of nurses and nurse managers. Findings: Nurses identified 53 core interventions, 50 of which are described in the Nurs- ing Interventions Classification (NIC). Altogether, two thirds of these interventions were in the NIC domain ‘Behavioral’ and the emphasis was on NIC classes ‘Coping Assistance’ and ‘Behavior Therapy,’ suggesting that nurses define providing psychosocial support as the core in their work. Conclusions: The findings indicate that the main role of nurses in the psychiatric outpa- tient care is to deliver psychosocial care for their patients. The lack of family interventions among the core interventions and the need to add the missing three interventions into the classification need more research in the future. Implications for nursing practice: This study helps to define nurses’ role in the psychiatric outpatient care. The findings can be used in developing nursing education programs. KEYWORDS Core interventions, Delphi Technique, Outpatients, Psychiatric Nursing, Standardized Nursing Terminology INTRODUCTION The need for psychiatric care has been rising, and it is estimated that more than one in six persons yearly suffer from mental health prob- lems (OECD/EU, 2018). Mental health care systems vary in the amount of services delivered in the inpatient and the outpatient setting. However, in many health care systems, there has been a reduction of time spent in psychiatric hospitals and an increased focus on providing community and outpatient care (WHO, 2018). This has changed the roles of nurses who work in the mental health care settings. Nurses play a central role in the delivery of psychiatric services, since they are the largest group of staff members working in psychiatric and mental health services (WHO, 2018). However, nurses’ roles in mental health care have been described as “difficult to clarify” (Hercelinskyj, Cruickshank, Brown, & Phillips, 2014; Santangelo, Procter, & Fassett, 2018; Simpson, 2005) and “ambiguous” (Hercelinskyj et al., 2014). These unclarified roles are said to have led to problems, such as becoming marginalized and difficulties in defining the nurses’ work (Bladon, 2018). One means to improve this situation is to better char- acterize nursing care through the use of standardized nursing language (Törnvall & Jansson, 2017). Nursing language and terminologies are a way to describe nurs- ing, including nursing interventions, systematically. Out of the many taxonomies available, the Nursing Interventions Classification (NIC) is the most widely studied classification describing nursing interventions (Tastan et al., 2014; Törnvall & Jansson, 2017). The NIC defines a nurs- ing intervention as “any treatment, based on clinical judgement and knowledge that a nurse performs to enhance patient/client outcomes” (Butcher, Bulechek, & Dochterman, 2018, p. xii). These include both direct and indirect nursing interventions (Butcher et al., 2018). Int J Nurs Knowl. 2020;1–8. © 2020 NANDA International, Inc. 1 wileyonlinelibrary.com/journal/ijnt