Individual augmentees (IAs), who presumably have lower social support or unit cohesion, were not at increased risk for PTSD or mental health symptoms following deployment compared with non-IA deployers. It is likely that social isolation was not highly influential among Navy IAs in this study.
http://ohrc.nu.edu/assets/resources/MilCohort IA Deployment May2012 JOEM.pdf
Chronic use of smokeless tobacco has been linked to poor military training performance, early discharge, and a host of medical problems from cancer to heart disease. Smokeless tobacco initiation occurred in 1.9% and persistent use in 8.9% of Millennium Cohort participants. The study showed that deployment, combat exposure, smoking, and symptoms of posttraumatic stress disorder increased the risk for smokeless tobacco initiation, while deployment and combat exposure increased the risk for persistent use.
http://ohrc.nu.edu/assets/resources/Millennium Cohort Smokeless Tobacco May2012 Addiction.pdf