Everything was used in Vietnam. Not all of it was provided by the Army doctors.
There is that, but I did read that stimulants were distributed by the Army. My high school history teacher was an infantry officer Vietnam vet. When he learned I was interested (my father was a Navy officer vet), he gave me books about Vietnam all year and had me give reports on them.
Once the bulb on the filmstrip project blew out, and he yelled, “Incoming!” and dived under a desk. I had a lot of nightmares that year.