**5. Directions for future research**

Over a decade ago, Shalev noted that the US Institute of Medicine judged the scientific evidence for the treatment of PTSD as below the level expected for such a common, disabling disorder. He observed significant progress was being made in the disorder's treatment, but was limited by an apparent treatment-ceiling-effect and a need for more efficacious application of better psychological theories [32]. Consistent with this view, the need to broaden the focus of enquiry in PTSD beyond anxietybased models was simultaneously identified in comprehensive reviews [31, 211].

As shown in this review, anger may be the predominant emotion for a majority of PTSD presentations [31] and it has vast costs that heavily impact on individuals, partners, families and communities. Yet, research on anger remains surprisingly sparse, with the most recent estimates suggesting it may equal as little 0.6 % of all PTSD publications [4]. There is an unequivocal need to increase research on anger in PTSD. This section suggests directions for future work.

An initial objective of research on PTSD must be to explicitly recognise the importance of anger to PTSD. Anger has been described as forgotten [212], unrecognised [9] and misunderstood [213] and the rate of research of anger in PTSD is lower than the level that might be reasonably expected on account of wide-ranging deleterious impacts. Explicit acknowledgement of anger's importance for prolonging PTSD, and as a factor influencing treatment outcome, will facilitate research on enhancing treatment protocols for treatment resistant clients. This proposition is supported by the work of various PTSD researchers who have illuminated the problem of anger, including Pitman and others [209], Elbogen, Johnson and Beckham [20], Forbes, McHugh and Chemtob [214], Morland and others [23, 197], Rona and colleagues [108] and Worthen and associate [215].

A second important research objective is to better understand the nature of anger and its relationship to imagery in PTSD. Despite its importance, the phenomenology of dysfunctional anger and imagery in anger in PTSD is not well described. Clearer identification of imaginal and linguistic cognitive processes and their relationship to anger-related PTSD in an integrated (visuo-linguistic) cognitive model of anger in PTSD would be another important step in research on anger in PTSD.

Research that identifies how anger in PTSD interacts with the characteristics of the PTE will be important in identifying differences in maintaining factors of PTSD after specific PTEs. It will also be useful to understanding the relationship between anger and cumulative trauma (e.g., due to vocation and occupation), the impact of perpetration versus experience of PTEs and the respective impact of exposure to PTEs versus how individuals are cared for post event.

The minting of PTSD in DSM-III created a research impetus that led to critical advances in knowledge of the disorder. That research impetus continues and DSM 5 has identified a dissociative PTSD subtype, sub-syndromal/prodromal PTSD and even a PTSD genotype [31, 211]. There is potentially significant value in exploring the possibility of an angry PTSD subtype to clearly identify individuals for whom anger is the primary emotional and evolve treatments to assist them.

#### *The Influence of Anger and Imagery on the Maintenance and Treatment of PTSD DOI: http://dx.doi.org/10.5772/intechopen.105083*

A third area for further inquiry relates to the linkages between anger and other trauma-related emotions. This review has shown that anger can occur in PTSD as a primary or secondary emotion connected to anxiety, responsibility-related emotions (especially shame and guilt) [43] and repugnance-related affects (like disgust and horror) [4, 44]. Understanding how anger is linked to other emotions and to symptom maintenance will aid the further refinement of treatment interventions for anger in PTSD. A full comprehension of the nature of anger in PTSD also requires a deeper understanding of the many cognitive processes associated with anger in PTSD. The application of imagery-based interventions to anger in the context of PTSD may be differentially efficacious depending on the cognitions, appraisals and affective causal pathways involved.

Based on the central argument of this review, a specific set of imagery-related research objectives could be pursued. As part of this, it will be important to establish what it is about visual imagery that promotes or hinders the efficacy of imaginal exposure in PTSD in the presence of anger. This exploration of imagery as a mechanism underlying anger's relationship to PTSD and the treatment of the disorder, will aid the development of a fuller account of the aetiology and maintenance of PTSD and offer new possibilities for enhanced treatment outcomes. Research is needed on psychological phenomena such as control, voluntary and involuntary experience of intrusions, the impact of content and process-related imagery and distress, cognitive style as expressed in the balance between imagery and linguistic-cognition and the association between personal style and imagery.

The dearth of theories and explanatory models about the role of imagery in anger in PTSD and any other mechanisms which may underlie their relationship are compelling grounds for testing and developing models and theories about different aspects of imagery in its interaction with anger in PTSD. So that imagery is integrated into descriptive and explanatory models with other important influences, like cognitive style and personality, it is important that such theories operate at multi-representational levels of explanation, are well operationalised and easily testable. Finally, it is important that focus be applied to the role of anger in PTSD as an explanation for the non-response to proven imagery-based treatments, like exposure. As part of this, any the means by imagery may reduce the treatment interference of anger must be investigated.
