Objective: Lack of consensus on the definition of mental health has implications for research, policy and practice. This study aims to start an international, interdisciplinary and inclusive dialogue to answer the question: What are the core concepts of mental health?

Design and participants: 50 people with expertise in the field of mental health from 8 countries completed an online survey. They identified the extent to which 4 current definitions were adequate and what the core concepts of mental health were. A qualitative thematic analysis was conducted of their responses. The results were validated at a consensus meeting of 58 clinicians, researchers and people with lived experience.

Results: 46% of respondents rated the Public Health Agency of Canada (PHAC, 2006) definition as the most preferred, 30% stated that none of the 4 definitions were satisfactory and only 20% said the WHO (2001) definition was their preferred choice. The least preferred definition of mental health was the general definition of health adapted from Huber et al (2011). The core concepts of mental health were highly varied and reflected different processes people used to answer the question. These processes included the overarching perspective or point of reference of respondents (positionality), the frameworks used to describe the core concepts (paradigms, theories and models), and the way social and environmental factors were considered to act. The core concepts of mental health identified were mainly individual and functional, in that they related to the ability or capacity of a person to effectively deal with or change his/her environment. A preliminary model for the processes used to conceptualise mental health is presented.

Conclusions: Answers to the question, 'What are the core concepts of mental health?' are highly dependent on the empirical frame used. Understanding these empirical frames is key to developing a useful consensus definition for diverse populations.