Lithium could be used to pacify an entire population in this way. A psychiatrist friend of mine once told me the military “looked into” spraying it over enemy territory in order to relax the opposing forces/people making them more susceptible to propaganda and infiltration. The issue is that too much causes overdose and the reactions are not helpful for invasion. The overdose reactions are heightened reflexes, seizures, agitation, slurred speech, rapid heartbeat, uncontrollable eye movements, confusion, delirium. This same psychiatrist friend told me that when the spraying is heavy, he can taste the lithium.