Martijn van Teffelen

Interpretation bias modification for hostility 127 6 controlled clinical trial (RCT) (Study 2) in people with clinical levels of hostility in which the efficacy of CBM-I in terms of hostile bias, benign bias and hostility outcomes (i.e., state and trait hostile thoughts, anger and aggression) is assessed. The primary hypothesis was that CBM-I would result in a greater increase in benign interpretations and a greater reduction in HIB compared to active control training (AC) in both studies. The secondary hypothesis in Study 2 was that CBM-I would lead to greater reductions in hostility and general psychiatric symptoms. We also expected greater reductions in state-anger in both studies. Lastly, we explored the carry-over effects in Study 2 of CBM-I on subsequent psychotherapy and expected increased quality of working alliance with participant’s therapists. STUDY 1 Methods Participants Participants were sampled in two ways. First, we recruited via flyers on a university campus. Second, to ensure sufficient variation at the extreme end of the hostility dimension, we additionally recruited participants with clinically relevant levels of hostility who were on a waiting list for treatment at two mental healthcare facilities in Maastricht, the Netherlands. Only men were included, to reduce sample heterogeneity. Exclusion criteria were a waitlist shorter than four weeks 1 , age below 18 and above 60 years and illiteracy. Clinically relevant levels of hostility were assessed by clinical judgement of their therapist. Patients were excluded from participation, also based on clinical judgement, if they showed signs of current psychosis or mania, alcohol or drug abuse/dependency, and acute suicide risk. The total sample consisted of N = 29 participants, of which n = 9 were lost to follow-up. The final sample consisted of N = 20 participants, of which n = 9 were in the CBM-I condition and n = 11 in the AC condition. Mean age was M = 40.2 ( SD = 9.6). The highest completed education level was low for n = 4, middle for n = 12, and high for n = 13 participants. Five participants were on active psychotropic medication. Age, educational level and use of psychotropic medication did not significantly differ between conditions ( p s > .071). Intervention arms CBM-I. This intervention condition consisted of eight sessions of benign intervention training, one session every three days. Prior to each session, participants engaged in an imagery task because a previous study reported that this increased the efficacy of CBM-I (Holmes et al., 2006). During this task, participants were instructed to imagine a lemon as 1 Our CBM-I intervention took place over the course of four weeks. To avoid confounding effects of other therapies, people with a waiting time shorter than four weeks were excluded.