Objectives There are several differences in health outcomes between UK and US personnel who have deployed to the recent conflicts in Iraq or Afghanistan. We compare published rates of health outcomes in UK and US military personnel and describe a UK and US collaboration project to examine differences in rates of posttraumatic stress disorder (PTSD), alcohol misuse and sleeping problems between UK and US military personnel who have experienced deployments to Iraq or Afghanistan.

Methods A methodological exploration of post-deployment health problems in UK and US military personnel, using individual person data from a UK longitudinal cohort study (Hotopf et al, 2006; Fear et al, 2010) and the US Land Combat Studies (Hoge et al, 2004; Hoge et al, 2007).

Results Rates of survey-based PTSD tend to be higher in US personnel, ranging between 8% and 15% compared to 4% and 6% in UK personnel (Sundin et al, 2010). In contrast, self-reported rates of alcohol use tend to be higher in UK compared to US military personnel; with rates of any hazardous consumption reported as 86% in UK male personnel compared to 25%-41% in US male personnel (Calhoun et al, 2008; Fear et al, 2007; Hawkins et al, 2010).

Conclusions Understanding the differences, as well as the similarities, between the UK and US Armed Forces is important, as it can influence the way military personnel are managed in both nations. It can also influence the way military personnel who have developed mental health problems as a result of their service are treated.