Skip to main content
KBS_Icon_questionmark link-ico

Limiting duration of overseas deployment prevents mental health problems in UK troops

Researchers from King’s College London Centre for Military Health Research (KCMHR) report that prolonged periods of deployment among the UK armed forces have fallen since the introduction of the “Harmony Guidelines” to limit tours of overseas duty – and this may have led to a reduction in mental health problems.

The researchers estimate that this drop in the number of troops experiencing prolonged tours of duty could have prevented 138 cases of post-traumatic stress disorder (PTSD), 453 cases of psychological distress, 309 cases of multiple physical symptoms, and 490 cases of alcohol misuse between November 2004 and September 2009. 

In 2007, research by the KCMHR showed that long operational tours—more than 13 months within a three-year time period; the maximum recommended time limit set by the UK Government and known as the Harmony Guidelines—were linked to serious mental health problems, alcohol problems, and family  difficulties. 

In this study, published in The Lancet Psychiatry, Roberto Rona, Professor of Public Health Medicine at King’s College London and colleagues re-examined whether length of deployment above these guidelines and frequency of deployment over three years had an effect on mental health. They assessed a random sample of 3982 regular military personnel (Army, Royal Navy, Royal Air Force, and Royal Marines) who had been on overseas tours during the three years prior to completing a questionnaire between November 2007 and September 2009, asking about their health including symptoms of post-traumatic stress disorder (PTSD), psychological distress, alcohol consumption, and problems at home.

The researchers found that breaching the Harmony Guidelines by deploying for 13 months or more over a three-year period almost halved from 22% in March 2005 to 12% in May 2008. 

Being deployed for more than 13 months over three years was associated with a significantly increased risk of developing PTSD or subthreshold PTSD, multiple physical symptoms, problems at home, and relationships and family problems compared to those deployed for shorter time periods, but not with psychological distress or harmful drinking. For example, rates of PTSD including subthreshold PTSD were around 12% in those deployed above the 13 month limit compared with 6% among those who spent less than five months in conflict.

Importantly, the number of deployments was not associated with worse mental health or problems at home. 

Professor Rona says, “The Harmony Guidelines can prevent mental illness in the UK Armed Forces and, since 2006, their introduction has prevented deployment of more personnel for longer than recommended in the guidelines. Monitoring of cumulative length of deployment could prevent an increase in levels of stress and mental illness in the UK military.”

For further information contact Claire Hastings, Press Officer at IoPPN, King’s College London, on +44(0)2078485377 or email

For full Article and Comment see: