Martijn van Teffelen

Imagery-enhanced cognitive restructuring: Protocol 101 5 INTRODUCTION Hostility is a personality constellation that consists of a tendency to experience angry affect, hold hostile cognitions and behave aggressively (American Psychiatric Association, 2013; Barefoot, 1992; Chaplin, 1982). Trait hostility consists of several lower-level dimensions: a cognitive (i.e., hostile intent), affective (i.e., anger) and behavioral (i.e., aggression) dimension. Hostility is associated with profound negative consequences, such as intimate partner violence (Henrichs et al., 2014), increased risk of coronary heart disease (Smith, 1992), and suicidality (Ammerman et al., 2015). One study in N = 3800 outpatients in the United States demonstrated that 21% self-reported moderate to severe aggressive behavior in the preceding week (Genovese et al., 2017). Of these 3800 outpatients the majority of patients were classified with major depressive disorder (42%), anxiety disorder (39%), and personality disorder (29%). Hostility rates in the same work were even higher in people with intermittent explosive disorder (67%), posttraumatic stress disorder (38%) and cluster B personality disorders (51%). It may therefore not be surprising that high levels of hostility is often a primary reason to seek treatment in mental healthcare institutions (Lachmund et al., 2005). The treatment of hostility can be considered challenging for a number of reasons. First, hostility poses a diagnostic problem. Traditional classification instruments such as DSM-5 and ICD- 11 do not include a ‘hostility disorder’. Instead, different aspects of hostility are described as symptoms of other clinical disorders. DSM-5, for example, includes hostility aspects in descriptions of intermittent explosive disorder, posttraumatic stress disorder, borderline personality disorder, paranoid personality disorder, antisocial personality disorder, disruptive mood dysregulation disorder and bipolar disorder. While some authors propose to include a ‘hostility disorder’ in future editions of classification instruments (DiGiuseppe et al., 2012), others propose to view hostility as a transdiagnostic phenomenon (American Psychiatric Association, 2013; Cassiello-Robbins & Barlow, 2016; Fernandez & Johnson, 2016; Vidal-Ribas et al., 2016). Second, hostility is been associated with premature treatment discontinuation (Arntz et al., 2015; Cassiello-Robbins et al., 2015; Putt et al., 2001). Third, hostility is positively associated with psychopathological severity (Cassiello-Robbins & Barlow, 2016). Last, evidence suggests that hostility may contribute to feelings of inadequacy in therapists (von der Lippe et al., 2008). Irrespective of the conceptual and clinical challenges that currently impact pathological hostility, the prominence of hostility as a clinical problem stresses the need for effective methods of intervention. Fortunately, cognitive behavioral therapy (CBT) programs have been developed to treat hostility and show favorable outcomes (Hofmann et al., 2012). However, 34% of patients who received cognitive behavioral treatment packages for hostility did not (or to a less extent) benefit from treatment (Hofmann et al., 2012). It is furthermore speculated that cognitive