In contrast, approximately ten to twenty percent of US troops are diagnosable with the condition, according to studies published in the New England Journal of Medicine and the Journal of the American Medical Association.
The first is that US troops may be involved in more dangerous combat duty and are therefore more likely to be traumatised.
However, they suggest other factors are also likely to be important.
US tours of duty are typically for 1 year, whereas UK tours are for 6 months. This means any combat-duty-related psychological stresses are likely to be extended in US personnel.
Further factors relate to the differences in the populations of the US and UK forces:
…the groups described in the US studies were demographically different from those described here. The US forces deployed to Iraq in both studies were younger, of lower rank, and contained more reservists than our UK sample. While less than 10% of the US sample had previous experience of deployment, more than two-thirds of the UK service personnel from both cohorts had been on previous deployments in a range of settings, including both war-fighting and peacekeeping duties. They therefore had much more experience of the stresses of military deployments, and might have been more resilient to these stresses.
In other words, US forces in Iraq are more likely to be made up of younger, non-professional soldiers, on longer tours of duty, with less combat experience, in more dangerous areas, when compared to their their UK counterparts – potentially making them more vulnerable to mental illnesses such as post-traumatic stress disorder.
Link to abstract of Lancet study on mental health of UK troops in Iraq.
Link to JAMA study on mental health of US troops in Iraq.
Link to NEJM study on mental health of US troops in Iraq.
Link to US National Center for PTSD Iraq War information page.