Adverse mental health outcomes and alcohol misuse among UK Armed Forces personnel: fourth phase of a 20-year cohort study of military personnel who served during the Iraq and Afghanistan conflicts

Objectives Twenty years since the start of UK Armed Forces participation in the Iraq and Afghanistan conflicts post-2001, the extent to which these deployments continue to impact mental health outcomes and alcohol misuse in UK military personnel is unknown. This is the reporting of the fourth phase, cross-sectional study of a longitudinal cohort study that has assessed the health and well-being of UK serving and ex-serving personnel since 2004. Methods Participants were eligible for the most recent phase (2022–2023) if they took part previously (2014–2016) and consented to recontact. Primary outcome measures included symptoms of common mental disorders (CMD), such as depression and anxiety, probable posttraumatic stress disorder (PTSD), complex PTSD (C-PTSD) and alcohol misuse. Results In the overall sample (n=4104, response rate=54.6%), CMD were the most prevalent outcome (27.8%), followed by probable PTSD (9.4%) and alcohol misuse (8.4%). The majority of PTSD experienced met the criteria for C-PTSD (72.7%). Ex-serving Regulars compared with serving Regulars reported a higher prevalence of PTSD (10.5% vs 7.4%, adjusted OR (AOR)=1.68, 95% CI 1.12 to 2.51) and C-PTSD (6.5% vs 3.9%, AOR=1.80, 95% CI (1.07 to 3.05); a higher prevalence of both disorders was also reported in serving/ex-serving Regulars whose last deployment to Iraq/Afghanistan was in a combat role. Conclusion Although the majority of those who deployed to Iraq or Afghanistan remain well, there is an enduring impact of combat deployment on PTSD. Attention should continue to be directed towards the prevention, early detection and treatment needs of this cohort.