2.3.2. NEO Five-Factor Inventory-3 (NEO-FFI-3)

The NEO-FFI-3 [87,88] provides a self-report measure of personality traits according to the Big Five theory of personality [56,89]. For the purposes of this study, we used a neuroticism scale with 12 items, each rated by the participant on a 5-point Likert scale ranging from 1 to 5, where 1 = “Strongly disagree” and 5 = “Strongly agree”, according to their pre-COVID-19 pandemic experience. Neuroticism scores were calculated by reverse scoring the appropriate items, summing all values to obtain raw scores (range: 12–60), computing z-scores, and finally calculating T-scores (M = 50, SD = 10) through a standardization process. Standardized coefficient alpha for Neuroticism was 0.87 (the Italian validation of the instrument reports α = 0.75 [88]). Because biological sex affects NEO-FFI-3 Neuroticism results but not much is known about the influence of gender identity, particularly in the case of gender variance, in calculating z-scores we applied the average and SD for the female population for our cisgender female participants, the average and SD for the male population for our cisgender male participants, and the total population average and SD for our non-cisgender participants.