The people who stay on an intimate basis with the troops at the pointy end are primarily med techs, physician assistants--more about physician assistants to come, I'm sure, in your study--and general duty medical officers.
The mental health team is usually centralized at Kandahar airfield and sees people on a referral basis. But they also go out when they can get transport. One of the riskiest things you can do in that theatre is move from place to place. The FOBs themselves are usually pretty secure once you're there. It's getting there, whether you take a helicopter or a vehicle, that can kill you. So movement is not something you want to do too much of.
The mental health teams do go and visit the FOBs periodically, but usually they stay centralized back in Kandahar airfield. The front-line providers are the med techs, physician assistants, and general duty medical officers; they are what we call “role one”. That just means they're the front-line guys.