The impact of posttraumatic stress disorder on impairment in the UK military at the time of the Iraq war

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Abstract

The aims of this study were to assess: (1) the relationship between PTSD and impairment, (2) whether there is a threshold in the association of PTSD score and impairment, and (3) whether any of the PTSD criteria are more strongly associated with impairment. We studied 10,069 service personnel from a representative sample of the British Armed Forces to assess the effects of the Iraq war. Participants completed the PTSD checklist (PCL), the general health questionnaire-12 (GHQ-12), the alcohol use disorder identification test (AUDIT) and five questions to assess impairment. 78% of those with a PCL-score of 50 or more endorsed at least one impairment item in comparison to 27% of those with a score below 50. The odds ratio (OR) of impairment in the PCL group with a score of 50 or more was 16.7 (95% CI 12.9–21.6). There was an increasing risk of impairment with an increasing category of PCL-score without a noticeable threshold. For each PTSD subscale: intrusiveness, avoidance/numbing and hyper-arousal, divided into four score categories, there was an increased association with impairment, but the association of avoidance/numbing with impairment was the greatest and independent of the other two criteria (OR 7.2 (95% CI 4.8–10.9). Having a good relationship with a partner had minimal effect on the level of association between PTSD and impairment. Functional impairment is a serious problem for those with PTSD. The impairment is not confined to those with the highest PCL-score. Avoidance/numbing is the criterion which makes the greatest independent contribution to impairment

Introduction

Functional impairment is a common feature of posttraumatic stress disorder (PTSD) in civilians (Amaya-Jackson et al., 1999, Breslau et al., 2004, Marshall et al., 2001, Stein et al., 1997) and military personnel (Caspi et al., 2007, Dohrenwend et al., 2006, Grubaugh et al., 2005, Schnurr et al., 2000). However, among military studies there is variation in the prevalence and level of severity of impairment in those with PTSD (Dohrenwend et al., 2006, Frueh, 2007). Impairment is not only a characteristic of PTSD patients, but also of those who do not entirely fulfill the diagnostic criteria, usually called partial PTSD (Breslau et al., 2004, Grubaugh et al., 2005, Marshall et al., 2001, Schnurr et al., 2000, Stein et al., 1997, Weiss et al., 1992;). Some commentators have emphasized that co-morbidities, including depression, may be partly responsible for this association (Momartin et al., 2004, North et al., 1999).

Most reports concerning PTSD and impairment in the military have been restricted to Vietnam veterans (Frueh, 2007) or to specific ethnic groups (Caspi et al., 2007). It has been reported that impairment is common among Vietnam veterans with current PTSD (Dohrenwend et al., 2006), but some have argued that the measurement scale used in that study was skewed towards identifying impairment (Frueh, 2007). This view is supported by the high percentage of those with PTSD whose level of impairment consisted of “some difficulty in social, occupational or school functioning but generally functioning pretty well”. Others have argued that this level of impairment is the appropriate threshold in veterans experiencing PTSD 11–12 years after the event (Kilpatrick, 2007).

The short forms of the quality of life questionnaire (the SF-12 or SF-36) (Ware et al., 1993) have been used in the military to assess quality of life (Boehmer et al., 2003, McKenzie et al., 2004, Proctor et al., 2001, Voelker et al., 2002), but rarely for inferring what impact PTSD has on personnel’s social and work functioning (Grubaugh et al., 2005, Schnurr et al., 2000). Whilst there is an implicit acceptance that those with PTSD will endure some degree of impairment, some studies have shown that numbing and avoidance may be more important in their contribution to the level of impairment than other PTSD criteria (Foa et al., 1995, Norman et al., 2007, North et al., 1999). It has been reported that endorsement of questions on numbing and avoidance is among the lowest prevalence in subjects who experienced a recent trauma (North et al., 1999, Schutzwohl and Maercker, 1999). We do not know whether these findings are relevant to a military population.

We report the results of a study carried out between 2004 and 2006 to assess the effect of the Iraq war on psychological symptoms (Hotopf et al., 2006). As well as assessing PTSD symptoms we used some items of the SF-36 to assess quality of life in relation to occupational and social functional limitations. We also assessed respondents’ satisfaction with long term relationships. The aim of this study is to assess the relationship between PTSD and functional impairment and whether there was a threshold in the association of PTSD score and impairment. We also examined whether any of the component criteria of the PTSD construct, intrusiveness, numbing/avoidance and hyper-arousal, were more strongly associated with impairment than other criteria, and the influence of co-morbidity and relationship satisfaction with a partner on any possible associations.

Section snippets

Sample

The study was based on the first wave of a cohort study of UK Armed Forces personnel comparing the health of those who participated in TELIC 1 (the codename used by the UK military for the major combat phase of the Iraq war between 18th January and 28th April 2003) with an era group selected from those who did not participate in TELIC 1 but were serving in the military at that time (Hotopf et al., 2006). We surveyed a random sample stratified by service and enlistment type (regular and

Results

Two hundred and three subjects were excluded from the analysis because of missing information on PTSD. Table 1 gives the distribution of impairment according to PTSD caseness, and PTSD caseness stratified by caseness for the GHQ-12 and/or severe alcohol problem, and for GHQ-12 but not PTSD caseness. 87.3% of the PTSD cases were also positive for GHQ-12, 43.9% were also positive for severe alcohol problem and 7.4% were positive for PTSD only. There was a marked increase in the percentage with

Discussion

PTSD caseness and each criterion of PTSD were strongly associated with impairment. There was an exponential relationship between PCL score and impairment, and each PTSD criterion and impairment, without an apparent threshold. There was a gradient in the association of each criterion of PTSD and functional impairment, the strongest association was with avoidance/numbing, intermediate with hyper-arousal and lowest with intrusiveness. The avoidance/numbing and hyper-arousal criteria, but not

Conflict of interest statement

Simon Wessely is Honorary Civilian Consultant Advisor in Psychiatry to the British Army (unpaid). Neil Greenberg is member of the Defence Medical Services. All other authors declare no competing conflict of interest.

Contributors

Roberto Rona was a principal investigator, planned and sought funding for the study, supervised aspects of data collection, designed the analysis and drafted the paper. Margaret Jones participated in the conduct of the research, carried out the analysis, and wrote the paper. Amy Iversen participated in the planning and conduct of the study; Lisa Hull participated in the conduct and planning of the study, Neil Greenberg participated in the planning of research and was involved with military

Role of funding source

The study was funded by the UK Ministry of Defence (MOD) Grant R and T/1/0078.

The MOD had no role in the study design, in the collection, analysis and interpretation of the results, and the decision to submit the paper for publication. The Defence Analytical Service Agency (MOD) provided the sampling frame and carried out the random selection of military personnel for this study following our instructions. We liaised with military personnel about the procedures to follow for contacting the

Acknowledgements

We thank the UK Ministry of Defence for their cooperation; in particular the Defence Medical Services Department, the Defence Analytical Service Agency, the Armed Forces Personnel Administration Agency, the Armed Forces Personnel Administration Agency, and Veteran’s Policy Unit. Matthew Hotopf and Simon Wessely are partially funded by the South London and Maudsley NHS Foundation Trust/Institute of Psychiatry NIHR (National Institute of Health Research) Biomedical Research Centre.

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