Mental Health and/or Mental Illness: A Scoping Review of the Evidence and Implications of the Dual-Continua Model of Mental Health

The dual-continua model of mental health suggests that mental illness and positive mental health reflect distinct continua, rather than the extreme ends of a single spectrum. The aim of this review was to scope the literature surrounding the dual-continua model of mental health, to summarise the evidence, highlight the areas of focus for individual studies and discuss the wider implications of the model. A search was conducted in PsycINFO (n = 233), PsycARTICLES (n = 25), Scopus (n = 137) and PubMed (n = 47), after which a snowballing approach was used to scope the remaining literature. The current scoping review identified 83 peer-reviewed empirical articles, including cross-sectional, longitudinal and intervention studies, which found overall support for superior explanatory power of dual-continua models of mental health over the traditional bipolar model. These studies were performed in clinical and non-clinical populations, over the entire life-course and in Western and non-Western populations. This review summarised the evidence suggesting that positive mental health and mental illness are two distinct but interrelated domains of mental health; each having shared and unique predictors, influencing each other via complex interrelationships. The results presented here have implications for policy, practice and research for mental health assessment, intervention design, and mental health care design and reform.