Back to basics in the field of loneliness: progressing conceptualisation and definition of the term – an umbrella concept analysis

. In the process, we identified the unidimensionality of loneliness and generated clarity regarding the opposite of loneliness ('unloneliness'). We call on researchers, policymakers and practitioners working in the field of loneliness, the wider field of interpersonal relationships or encountering loneliness in other fields of activity, across the globe, to employ the novel conceptualisation and theoretical definition as a foundation for activities to further progress understanding and addressing of loneliness. We also encourage consideration of unloneliness, when undertaking such activities.