The largest and most up-to-date study of suicides among depressed veterans provided important new data that may help guide screening and treatment for all veterans. Published in American Journal of Public Health, the study found that the predictors of suicide among veterans in depression treatment differ from those seen in the general American population, with younger, white, non-Hispanic men having the highest risk among the veterans.
Veterans with substance abuse issues, and those who had been hospitalized for psychiatric reasons in the year before their depression diagnosis, also had a higher suicide risk. Surprisingly, older veterans who had been diagnosed with post-traumatic stress disorder (PTSD) in addition to depression had a lower overall rate of suicide than those without a PTSD diagnosis, perhaps because they were more likely to receive care through Veterans Affairs (VA) PTSD programs.
The study was conducted by researchers from the VA Ann Arbor Healthcare System and the University of Michigan Health System and the University of Michigan Depression Center. The researchers analyzed comprehensive data from 807,694 veterans of all ages diagnosed with depression and treated at any VA facility nationwide between 1999 and 2004. The data are from the VA’s National Registry for Depression.
The researchers found that 1,683 of the depressed veterans committed suicide during the study period, representing 0.21% of the depressed veterans studied. They then analyzed the characteristics of all the depressed veterans who committed suicide, and calculated suicide hazard ratios and suicide rates per 100,000 person-years for each subgroup.
The study divided veterans into three age groups: 18 to 44 years, 45 to 64 years, and 65 years or older. It did not assess whether they had served in combat during a particular conflict, although the existence of a disability connected to military service was considered. The depressed veterans who did not have a service-connected disability were more likely to commit suicide than those with a service-connected disability. This may be due to greater access to treatments among service-connected veterans, or more stable incomes due to compensation payments.
When the researchers calculated suicide rates over the entire 5.5 year study period, they were much higher for men (89.5 per 100,000 person-years) than for women (28.9), and higher for whites (95 per 100,000 person-years) than for African Americans (27) and veterans of other races (56.1). Veterans of Hispanic origin had a lower rate (46.28 per 100,000 person-years) of suicide than those not of Hispanic origin (86.8). Adjusted hazard ratios also reflected these differences.
The initial findings revealed a suicide rate of 68.16 per 100,000 person-years for depressed veterans who also had PTSD, compared with a rate of 90.66 for those who did not. This surprising finding led the researchers to examine whether specific subgroups of depressed veterans with PTSD had higher or lower suicide risk. Further examination demonstrated that the protective effect of having PTSD in addition to depression was strongest among veterans in the two older age groups.
The authors said the study did not reveal a reason for this protective effect, but they theorized that it may be due to the high level of attention to PTSD treatment in the VA system and the greater likelihood that patients with PTSD will receive psychotherapy.