Response rate (Figure )
Twenty four of the 1107 participants were ineligible (10 were deselected due to invalid selection into the Phase 1 study, 3 had died and 11 had incomplete Phase 1 data for their PCL or GHQ responses (Figure )). One hundred and eleven declined to participate, 127 could not be traced despite multiple attempts and 24 were unavailable during the interview period due to deployment/training. The final sample consisted of 821 participants. The response rate was 74.2% and the adjusted rate was 75.8%.
The characteristics of study responders (Additional file 1
: table S2)
Uni-variable analysis of responders and non-responders based on their phase 1 questionnaire responses showed that compared to responders, non-responders were younger, more likely to hold a lower rank, and be regular personnel. After adjustment, only younger age remained a significant predictor of non-response. There was no difference in phase 1 health outcomes between those who responded and those who did not.
The prevalence of common mental disorders and PTSD symptoms (Table )
The weighted prevalence of any common mental disorder or PTSD symptoms in the phase 1 KCMHR military health study was 28.9%, and 4.8% for PTSD symptoms. Alcohol abuse was the most common mental disorder (18.0%), followed by any neurotic disorder (13.5%). Within neurotic disorders, major depressive disorder was less common than milder depressive disorders (3.7% versus 7.3%). Panic (1.1%) and somatisation di sorders (1.8%) were relatively uncommon.
Mental health disorders in the KCMHR military health study, weighteda prevalence (%) and 95% confidence interval (CI)
Socio-demographic and military correlates of mental disorders (Tables and )
PTSD symptoms were associated with being male, lower educational attainment, having greater pre-enlistment vulnerability and being in the Army. Neurotic disorders were associated with lower educational attainment, greater pre-enlistment vulnerability, holding a lower rank, and being in the Royal Air Force. Alcohol abuse was associated with younger age, being male, not being in a relationship, greater pre-enlistment vulnerability, holding a lower rank, being in the Army, having a combat or combat support role and not being medically downgraded.
We present the deployment status analysis by engagement type due to our previous finding of a health effect among reserves [9
]. The unadjusted PTSD prevalence was associated with deployment when regulars and reserves were examined together due to an increase in prevalence in those who deployed on TELIC 1, and other recent deployments (predominately deployment to Afghanistan). Analysis by engagement type shows that this effect is restricted to reserves only. There was no effect of deployment on the prevalence of neurotic disorders or alcohol abuse.
The association between PTSD symptoms and deployment persists for TELIC 1 and other recent deployments when regulars and reserves are examined together after adjustment. Repeating this analysis by engagement type, the deployment effect was observed for reserves only. There was no effect of deployment on the prevalence of neurotic disorders or alcohol abuse.
Weighteda prevalence of mental health disorders in the KCMHR military health study by key demographics, % and 95% confidence intervals (CI)
Associations of PTSD symptoms with status and deployment history, odds ratio (OR)a and 95% confidence intervals (CI)
UK versus US comparisons (Table )
We compared our data with the US Post Deployment Health Reassessment Study (PDHRA) [20
], specifically Army personnel who had served in Iraq. The UK sample was older than the US sample but the two samples were similar with regards to gender and marital status. Deployment experiences of regular forces were broadly similar, except that UK personnel were more likely to report that they felt in danger of being killed. US reserve forces reported witnessing someone wounded or killed and discharging their weapon significantly more than UK reserves, while feeling in danger of being killed was more frequently reported among UK reserves.
The rates of depressive disorder and suicidal ideation were comparable between the US and UK for both regulars and reserves. Rates of PTSD symptoms were not significantly different amongst regulars but they were significantly higher for US military reserves than UK reserves. However, this difference disappears when the samples are further stratified by whether or not reservists discharged their weapon in combat (data available from authors). Fair or poor assessment of health based on the SF-36 were comparable for UK and US regulars, but significantly more frequently reported in US reserves than their UK reserve counterparts.
Combat experiences and mental heath for Army personnel post deployment to Iraq by regular/reserve status, UK vs. US dataa, mean or percentageb, with 95% confidence intervalc