BackgroundDementia is currently incurable, irreversible and a major cause of disability for the world's older population. The association between mental health difficulties, such as post-traumatic stress disorder (PTSD) and major depressive disorder (MDD), and dementia has a long history within the civilian population. Despite the increased importance of this link within the military veteran population, who suffer a greater propensity of mental health difficulties and consist largely of over 65s, attention is only recently being paid to the salience of such an association for this group. This paper aims to explore the relationship between PTSD and MDD with dementia within the military veteran population.MethodA systematic review was conducted on articles from 1990 to July 2016 on MEDLINE, EMBASE, EBSCO and Web of Science electronic databases with an update conducted in February 2017.ResultsSix empirical studies were identified from the review, the majority of which originated from the USA. Five of the studies asserted that veterans with a diagnosis of either PTSD or MDD are at a significantly greater risk of developing dementia than ‘healthy’ controls. The final study, conducted in Australia, found only a small, but non-significant, correlation between earlier MDD and future dementia, but no concurrent correlation.ConclusionsWhile causality cannot be determined, it is likely that PTSD and depressive disorders are related to an increased risk of dementia in military veterans. Potential pathological explanations and risk factors are reviewed and the clinical and neuroscience implications of these findings are explored.

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Some of the more negative findings could have implications in terms of seeking help for stress-related problems at an early stage, which is counter-productive to the military's genuine attempts to foster the psychological welfare of its employees. Some concerns could be alleviated by better and more timely stress education, preferably early on in a commander's career, so that positive attitudes to stress and stress-related problems can be formed and any negative attitudes changed, thereby bringing about a change in organisational culture in relation to stress. Some of the study's concerns were addressed by the Operational Health Strategic Surveillance Committee which advised on operational health aspects of OP TELIC.

Despite the importance of military leaders in moderating the impact of deployment stressors on unit members, little attention has focused on the training leaders receive in managing unit stress. As part of a NATO Research Panel (Human Factors and Medicine (HFM)-081/Research and Technology Organization Task Group (RTG)), 16 nations participated in a needs assessment survey of military leaders who had returned from an operation within the previous 2 years. Findings from 172 leaders emphasized the lack of training specifically geared for leaders to address operational stress issues for unit members and their families and the need for integrated mental health support across the deployment cycle. In general, most leaders regarded stress-related mental health problems as normal and were supportive of help-seeking. The information obtained here was used to develop a Human Factors and Medicine -081/RTG Leader's Guide on operational stress.

These results suggest that while the overall rates of self-reported mental health disorders were similar in FMs and RLMs, FMs reported more PTSD symptoms than all other roles, which may have been related to working in more hostile environments in more challenging roles while deployed and their experiences on returning home.