A declassified Pentagon report, obtained by a private citizen under the Freedom of Information Act, shedded new light on some of these "non-lethal" weapons.
The report (pdf file) :
Bioeffects of Selected Non-Lethal Weapons - US Department of Army FOIA (HERE)
Report also at:
http://www.wired.com/images_blogs/dangerroom/files/Bioeffects_of_Selected_Non-Lethal_Weapons.pdf
More information on the "denial systems" weaponry:
WIRED article
"Report: Nonlethal Weapons Could Target Brain, Mimic Schizophrenia"
extract:
"Application of the microwave hearing technology could facilitate a private message transmission. It may be useful to provide a disruptive condition to a person not aware of the technology. Not only might it be disruptive to the sense of hearing, it could be psychologically devastating if one suddenly heard ‘voices within one’s head.’"
Voices in your head disturbing? Heck, yeah, considering it’s something most people associate with schizophrenia. The age-old question is whether such a weapon is possible. According to the report, it’s not only possible, it’s already been demonstrated in crude form:
