Military psychologists use psychological research to identify, treat, prevent, and combat mental, emotional, and developmental issues with military personnel and units. Military psychologists can be deployed with active duty troops or they can work in hospitals and government agencies, and they assess individuals to identify things like emotional trauma, stress disorders, traumatic brain injuries and many other awful side-effects of war. They research behavior, emotions, and social development to try and nip serious issues in the bud before they become a problem.