Martijn van Teffelen

Hierarchical structure of hostility 27 2 METHODS Participants Participants were sampled in two ways. First, participants were recruited from the general population in Maastricht, the Netherlands through advertisement. Second, ensuring a representative distribution with enough variation at the extreme end of the hostility dimension (i.e., an estimated 12.4% of the Dutch population show signs of clinically relevant hostility, given that in the Netherlands an estimated 24.5% of people suffer from a mental disorder (i.e., anxiety, mood, eating, personality, and somatoform disorders) in one year (Gustavsson et al., 2011). Of these individuals an estimated 51% report moderate levels of anger (Posternak & Zimmerman, 2002)), we actively recruited participants with increased and clinically relevant levels of hostility from two mental health facilities in the Maastricht area (i.e., METggz and U-Center). Patients with a score above 1.22 on the hostility subscale of the Personality Inventory for DSM-5 (PID-5H) were eligible to enter the study. This cutoff equals 1 SD above the observed mean in a Danish population (a comparable population to the Netherlands) and approximates the mean in a clinical population (Bach et al., 2016). Exclusion criteria were age younger than 18 and higher than 60, and illiteracy. Patients were excluded from participation by clinical judgement in the mental health facility if they showed signs of current psychosis or mania, alcohol or drug abuse/dependency, and acute suicide risk. For EFA, a minimum sample size of N = 300 1 is suggested (Tabachnick & Fidell, 2007). In total, we recruited n = 347 people from the general population and n = 30 patients with clinically relevant levels of hostility. One patient withdrew consent from the study, so the final sample consisted of N = 376. Sample characteristics are shown in Table 1. Statistical analyses showed that, compared to non-patients, patients were less often female, lower educated, student, and were more often using active psychotropic medication. Materials State Trait Anger Expression Inventory-2 In the 10-item trait anger scale of the State Trait Anger Expression Inventory-2 (STAXI-2T) (Spielberger, 1999) items (e.g., “I am hot-headed”) are scored on a 4-point Likert scale ranging from one (not at all) to four (very much). Internal consistency, test-retest reliability (e.g., α = .72 - .96) and concurrent validity are good and adequate construct validity has been demonstrated (Lievaart et al., 2016; Spielberger, 1999). 1 We calculated the required sample size for correlational analysis at N = 135, with α = .01, β = .1, expected ρ = .3, and anticipated dropout = 10%.