The Pemberton Happiness Index

(PHI; Hervás & Vázquez, 2013) was used as a measure of positive mental health. The PHI includes 11 retrospective items related to ‘remembered well-being’ (i.e., general hedonic, eudaimonic and social well-being) on an 11-point Likert scale. In this study the Cronbach’s alpha was excellent (α = 0.93).

To explore the factorial structure of the TILS, the three items were subjected to a Principal Components Analysis (PCA) and the decision regarding the number of factors to extract was made also using both K = 1 criteria and Parallel Analysis method (Hayton et al., 2004). Regarding psychometric properties, internal consistency reliability and Test-retest reliability were analysed, by calculating Cronbach’s alpha (α), and by estimating the intraclass correlation coefficient (ICC) with 95% CI between the two administrations of the test, respectively. We examined the convergent validity of the scale by using the bivariate correlation analysis with the other related variables. Finally, to analyse the differences in the TILS scores according to gender and age, as well as education, income, employment status and history of mental health difficulties, a two-way between-groups and one-way analyses of variance were carried out. Analyses were conducted using the SPSS 23 program.