suritozole

Said to have the opposite interaction of Valium or benzodiazepine. If anything it might be seen as a chemical-weapon.

has anxiogenic and convulsant properties,[1] and is used in scientific research to induce anxiety so that new anxiolytic medications can be tested,[2] and to produce convulsions so that anticonvulsant medications can be tested

In theory the interaction is very similar to the chemical used in the Batman series by the scarecrow. A chemical that would induce massive anxiety or panic attacks. It's something so obscure that if it were used for clandestine testing on populations it would spike anti-anxiety medications and also be very desirable for social and behavioural engineers.

Keep in mind, though controversial there is the case of a French town's mass LSD poisoning being linked back to the CIA, and other experiments where large populations were sprayed with bio/chemical weapons.