Objectives Determine impact of operational tours on referral rates to MOD Departments of Community Mental Health (DCMH); Identify military populations at risk for mental health problems; Assess impact of length of time from deployment to referral and Is there evidence for ‘bow-wave’ of PTSD resulting from operational deployments?

Methods This is a cohort study based on administrative data for period 2007–2010. Records for Service personnel who attended an MOD Department of Community Mental Health (DCMH) facility were linked to the MOD personnel administration system to identify all those who had deployed prior to their mental health referral.

Results More than 4000 Service personnel attended a DCMH following deployment to either Iraq or Afghanistan; 51% were assessed with a neurotic disorder. Population groups at risk included Army personnel, females and lower ranks. First 12 months showed increase in referrals for neurotic disorders (of which 61% adjustment disorders; 11% PTSD), after 24 months referral rates return to baseline. Significant impact of PTSD post deployment, rate ratio 15.5 (95% CI 4.8 to 49.8) for those deployed to Afghanistan and 9.9 (95% CI 3.1 to 32.3) for those deployed to Iraq compared to those not deployed on operations.

Conclusions Groups at risk include females, Army personnel and other ranks. Rates of referral are highest in 12 months post deployment, adjustment disorder greatest impact on DCMH activity. No evidence for a bow-wave but evidence for increasing impact of PTSD in those who have deployed on operations.