Twenty years after UK Armed Forces participation in the Iraq and Afghanistan conflicts, there remains an enduring impact of combat deployment on PTSD, with common mental disorders being the most prevalent outcome (27.8%) and the majority of PTSD cases meeting criteria for complex PTSD (72.7%).
Common mental disorders (CMD) were the most prevalent adverse mental health outcome in the overall sample, followed by probable PTSD and alcohol misuse.
The majority of probable PTSD cases met the criteria for complex PTSD (C-PTSD).
Ex-serving Regulars reported significantly higher prevalence of probable PTSD compared with serving Regulars.
Ex-serving Regulars reported significantly higher prevalence of C-PTSD compared with serving Regulars.
Higher prevalence of both PTSD and C-PTSD was reported in serving and ex-serving Regulars whose last deployment to Iraq or Afghanistan was in a combat role.
Despite the enduring mental health impacts identified, the authors noted that the majority of those who deployed to Iraq or Afghanistan remain well.
This research followed UK military personnel who served during the Iraq and Afghanistan conflicts over a 20-year period, with this latest phase collecting data in 2022-2023 from over 4,000 participants. The study found that about 1 in 4 participants showed symptoms of common mental health problems like depression and anxiety, roughly 1 in 10 had probable post-traumatic stress disorder (PTSD), and about 1 in 12 had alcohol misuse problems. Notably, nearly three-quarters of those with PTSD had a more severe form called complex PTSD (C-PTSD), which involves additional difficulties with emotional regulation and self-perception beyond standard PTSD symptoms. The research found that veterans who had left military service had significantly higher rates of PTSD and C-PTSD than those still serving — about 40-80% higher odds after accounting for other factors. Those whose last deployment in Iraq or Afghanistan involved a combat role also had higher rates of both PTSD and C-PTSD, regardless of whether they were still serving or had left. This suggests that the nature of deployment duties and the transition out of military service are important factors in long-term mental health outcomes. This research suggests that the mental health consequences of the Iraq and Afghanistan conflicts are still being felt two decades later, particularly among veterans who have left the military and those who served in direct combat roles. While most personnel who deployed remain well, the findings highlight an ongoing need for mental health support, screening, and treatment services targeted at this population — especially for C-PTSD, which requires specific therapeutic approaches and may be underidentified in routine care.
Sharp M, Jones M, Franchini S, Leal R, Hull L, Molloy N, et al.. (2026). 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.. Occupational and environmental medicine. https://doi.org/10.1136/oemed-2025-110647