Service members with one or more mental health disorders prior to deployment were two- and-a-half times more likely to screen positive for PTSD post-deployment compared to those with no mental health disorders, after controlling for pre-deployment PTSD, physical injury severity and a host of other risk factors.

Participants who engaged in less physical activity were more likely to screen positive for PTSD. Those who reported at least 20 minutes of vigorous activity twice a week had significantly reduced odds for new-onset and persistent PTSD symptoms.

Deployment as a Navy individual augmentee (IA) was not significantly associated with newly reported PTSD or symptoms of mental health problems (including PTSD, depression, panic or other anxiety and alcohol-related problems) compared with non-IA deployment.

Analysis of U.S. service members who had deployed either once or multiple times revealed that both groups shared very similar PTSD trajectories over time, with the vast majority (83% single deployers, 85% multiple deployers) displaying a low-stable (resilient) symptom pattern that lasted from pre-deployment to several years post-deployment. The other PTSD symptom trajectory patterns included moderate-improving (8%, 8.5%), worsening-chronic (6.7%, 4.5%), high-stable (2.2% single deployers only) and high-improving (2.2% multiple deployers only).

Military healthcare professionals have similar rates of new-onset PTSD or depression compared to those in other military occupations. Similar to other types of military personnel, combat exposure was the key factor that increased the rates of new-onset PTSD/depression in this sample, as deployed healthcare professionals with combat exposure had twice the odds of new-onset PTSD/depression compared to those deployed without combat exposure.

Among service members with no history of mental disorder diagnosis or psychotropic medication prescription, and who screened negative for depression, anxiety, PTSD and panic pre-deployment, 3.4% developed PTSD, less than 1% developed anxiety and less than 2% developed depression after first deployment. Service members who reported sleeping fewer than six hours per night pre-deployment were significantly more likely to develop PTSD than those sleeping seven hours per night. Additionally, those reporting insomnia symptoms pre-deployment were at higher risk for new-onset PTSD, anxiety and depression.

Analysis of factors associated with death by suicide during and after military service found that suicide was most common among those with bipolar disorder, depression and alcohol-related problems. Additionally, death by suicide was associated with fewer cumulative days of deployment, the occupation of combat specialist, deployment experience pre-2001 and male gender. Overall, 12.8% of the deaths in the current sample were due to suicide.

Recent research from the Millennium Cohort Study found that military personnel who deployed with combat experiences were more likely to report back pain after deployment than service members who deployed without combat experience. Study findings were recently published in the November issue of Spine.

A new partnership between DoD and VA medical researchers achieves a milestone with its first joint publication, which examines post-traumatic stress disorder (PTSD) symptoms in veteran and active duty populations. The study will be published in the Journal of Psychiatric Research, June 2017.

The Millennium Cohort Program Team was awarded the award for Outstanding Research Accomplishment (Team Military) at the 2023 MHSRS Conference.