Loneliness refers to the perception of mismatch between the perceived and desired quantity and quality of meaningful relationships. Currently, the golden standard measure to assess loneliness is the University of Los Angeles Loneliness scale version 3 (UCLA v3). The aim of this study was to analyze the psychometric properties and the factor structure of UCLA v3 for the European Portuguese population. A sample of 282 participants was surveyed in Portugal. Analyses showed internal consistency was optimal for the Portuguese population: Cronbach’s α = .91 and McDonald’s ω = .91. Confirmatory factor analysis (CFA) supported a single global factor for loneliness and optimal fitness. Multi-group CFA indicates invariance across sex. Floor and ceiling effects were largely absent. Loneliness correlated with well-established mental health indicators such as psychological stress, depressive and anxiety symptomatology or psychological inflexibility. The findings support UCLA v3 as a reliable and valid measure of loneliness in the Portuguese population.

Angeles Loneliness scale version 3 (UCLA v3). Objective. The aim of this study was to analyze the psychometric properties of UCLA v3 for the European Portuguese population. Method: A sample of 282 participants was surveyed in Portugal. Results: Confirmatory factor analysis (CFA) supported a model portraying a global loneliness bifactor solution for positive and negative wording items, which achieved optimal fitness. Multi-group CFA indicates scalar and metric invariance across gender. Loneliness test scores (global score, positive items and negative items) correlated with well-established mental health indicators such as psychological stress, depressive and anxiety symptomatology, or psychological inflexibility. Internal consistency of the loneliness test scores was optimal for the global measure (α = .91; ω = .91) as well as for the positive (α = .87; ω = .87) and the negative factors (α = .86; ω = .88). Conclusions: Results support UCLA v3 as a reliable and valid measure of loneliness for future research studies interested in examining the prevalence of loneliness and impact in health in the context of Covid-19 in the Portuguese population and as a health indicator in health promotion and clinical interventions.