Long military deployments may affect mental health

Reports that long periods of overseas deployment in the armed forces are causes of stress, alcoholism, and other domestic problems appeared on the BBC and in several daily newspapers.

The news reports were  based on research that found that soldiers deployed for more than 13 months over a three-year period were more likely to “turn to drink, suffer post-traumatic stress disorder and have family rows” (Daily Express ). The Daily Mail included the statistics that these troops were 58% more likely to develop post-traumatic stress disorder (PTSD) and “face a 35 % greater chance of becoming alcoholics”.

In general, it was reported that those deployed for longer than expected were twice as likely to suffer problems.

The research that these reports were based upon presents reliable evidence about the links between mental health and deployment in the armed forces. However, this study cannot conclude that the duration of time spent overseas is the single cause, and the other links with combat exposure, type of deployment and problems at home also provide clues to how policies might be developed further.

Where did the story come from?

The study was conducted by Roberto Rona professor of public health, and colleagues at King’s College London. It was funded by the UK Ministry of Defence, who took no part in the conduct of the study.

The research was published in the peer-reviewed_ British Medical Journal_ .

What kind of scientific study was this?

This was a cross sectional study that has been carried out as the first part of a longer study. The study was designed to see how frequency and duration of overseas tours affects the mental health of personnel deployed in the armed forces.

The researchers looked at the mental health of soldiers over the past three years, specifically comparing a group deployed to Iraq between  January 18 and April 28 2003, and a group not deployed to Iraq. Attempts were made to obtain a representative sample of members of different services (for example Royal Air Force, Royal Marines) and type of enlistment (regular or reserve).

Questionnaires covering aspects such as experiences in the military, periods of deployment and health outcomes were sent to 4,722 soldiers on Iraq operations and 5,550 soldiers not deployed to Iraq.

About 60% responded to the questionnaires, allowing responses of 5,547 soldiers to be examined. The main outcomes examined were general psychological health, PTSD, physical symptoms, or alcohol use. To assess how this related to deployment, researchers looked at the locations the soldiers were sent to, and frequency and periods of time spent away to see whether soldiers were being sent away for longer periods than recommended by guidance. Different armed services were also examined separately.

What were the results of the study?

The research found that those sent away for a total period of greater than 13 months over the past three years were more likely to suffer from PTSD (58% more likely); report psychological symptoms or suffer severe alcohol problems (each 35% more likely) and have several physical symptoms (49% more likely). Duration of deployment, not number of times deployed was the important factor.

The increase in risk of these problems was partly explained by other factors (including problems at home, whether deployment was to war or for peace enforcement, and time spent in close contact with enemy). When these other factors were taken into account, the duration of deployment had no effect on psychological problems. However, no factor on its own was responsible for the effect on psychological health.

The researchers also found that longer duration of deployment meant more problems at home. However, when factors such as type of deployment and enemy contact were taken into account this association was no longer significant.

What interpretations did the researchers draw from these results?

The researchers concluded that there was a strong link between deployment for more than 13 months over a three-year period and development of psychological problems.

Factors including type of deployment (i.e. exposure to combat) and whether those studied had domestic problems did seem to influence the connection between deployment and development of psychological problems,

They suggest that their research shows that “adherence to a clear and explicit policy on duration of each deployment may have beneficial effects on mental health”.

What does the NHS Knowledge Service make of this study?

This is reliable and interesting research. There are a few points to be aware of when considering this evidence, which the researchers acknowledge:

• That the type of activity undertaken or things experienced during deployment is likely to be highly variable and the researchers did not have independent information on the intensity of combat; they were relying on the participant’s subjective response
• When considering the cause of ill health, it is not always possible to tell from studies like this which event came first, e.g. the soldier may have been suffering from mental health problems before the period of deployment. Although there was no data on psychological  symptoms before data, this explanation seems unlikely to explain such a consistent and specific effect.
• Although this research cannot prove that duration of deployment is the single cause of psychological problems in the armed forces, it suggests that, the length of time spent overseas in areas of conflict and the other related factors, such as a soldier’s expected time away need further consideration.