Martijn van Teffelen

Imagery-enhanced cognitive restructuring: Efficacy 75 4 INTRODUCTION Hostility, a trait dimension that consists of a tendency to (I) behave aggressively, (II) experience angry affect and (III) hold cynical cognitions (e.g., hostile beliefs), can be considered a transdiagnostic (i.e., cross-diagnostic) phenomenon in mental disorders (Cassiello-Robbins & Barlow, 2016). Cognitive behavioral therapy (CBT) programs have been developed for hostility and show favorable outcomes (Hofmann et al., 2012). One CBT intervention, cognitive restructuring (CR), focuses on changing hostile cognitions. Within CR, patients are encouraged to identify and challenge hostile cognitions in past events that triggered anger and/or aggression, for example by gathering evidence for and against a hostile cognition. A meta-analysis across 23 studies showed that CR is effective in reducing hostility with moderate to large effects ( d = 0.51 to 1.87) (DiGiuseppe & Tafrate, 2003). However, this meta-analysis did not systematically assess risk of bias. Also, the overall 66% response rate (i.e., a symptom reduction of at least 50%) of CBT for hostility suggests that there remains a significant number of patients who fail to benefit from CBT (Hofmann et al., 2012). Moreover, hostile beliefs may concentrate more on fairness, blaming, justification and cathartic expression rather than the interpretation of facts (DiGiuseppe et al., 1994). For this reason, CR for hostility may more challenging than for instance CR for anxiety-related problems. In the present work, we aim to investigate whether the efficacy of CR for reducing hostility can be further improved by additional other treatment components. Previous work suggests that enhancing CR with mental imagery is a promising candidate for increasing its efficacy in reducing hostility. Indeed, the idea of integrating mental imagery in CR is not new (Edwards, 1990) and has been empirically validated for anxiety- and trauma-related disorders. That is, incorporating mental imagery during CR for social anxiety disorder patients led to greater symptom reduction compared to traditional CR (e.g., McEvoy et al., 2015; McEvoy & Saulsman, 2014), but see McEvoy et al. (2020) for contradictory evidence. Additionally, integrating the use of mental imagery into existing treatment protocols for childhood trauma related syndromes or disorders increased the effectiveness of several other interventions such as imaginary exposure and imagery rescripting (Arntz & Weertman, 1999; Ehlers et al., 2005; Smucker et al., 1995). Furthermore, evidence suggests that imagery plays an important role in angry affect and hostility. For example, a qualitative analysis of emotions and thoughts reported during the recall of intrusive mental images demonstrated that recalling intrusive mental images positively relates to experiencing a variety of affect, including anger (Holmes et al., 2005). Also, a literature review suggests that mental images of autobiographical memories generate a stronger emotional response than its` verbal-linguistic representations (Holmes & Mathews, 2010). Previous work suggesting that mental imagery is a promising candidate