Contribution of mental and physical disorders to disability in military personnel

Combat operations in Southwest Asia have exposed millions of military personnel to risk of mental disorders and physical injuries, including traumatic brain injury (TBI). The contribution of specific disorders to disability is, however, uncertain.

To estimate the contributions of mental and physical health conditions to disability in military personnel.

The sample consisted of military personnel who participated in the cross-sectional 2013 Canadian Forces Mental Health Survey. Disability was measured using the World Health Organization Disability Assessment. The International Classification of Functioning, Disability, and Health was used to classify participants with moderate/severe disability. Chronic mental disorders and physical conditions were measured by self-reported health professional diagnoses, and their contribution to disability was assessed using logistic regression and resulting population attributable fractions.

Data were collected from 6696 military members. The prevalence of moderate/severe disability was 10%. Mental disorders accounted for 27% (95% confidence interval [CI] 23-31%) and physical conditions 62% (95% CI 56-67%) of the burden of disability. Chronic musculoskeletal problems 33% (95% CI 26-39%), back problems 29% (95% CI 23-35%), mood disorders 16% (95% CI 11-19%) and post-traumatic stress disorder (PTSD) 9% (95% CI 5-12%) were the leading contributors to disability. After-effects of TBI accounted for only 3% (95% CI 1-4%) of disability. Mental and physical health interacted broadly, such that those with mental disorders experienced disproportionate disability in the presence of physical conditions.

Chronic musculoskeletal conditions, back problems, mood disorders and PTSD are primary areas of focus in prevention and control of disability in military personnel.