Aggressive behavior following exposure to cholinesterase inhibitors

The authors report four instances of significant, essentially unprovoked aggressive behavior, including two homicides, following exposure to cholinesterase inhibitors. No subject had a history of violent behavior, antisocial personality, or major psychiatric or neurologic disorder. After anticholinesterase exposure ceased, all showed sincere remorse for their actions, and none has since engaged in aggressive or psychopathologic behavior. Well-controlled experimentation in animals suggests that enhanced activation of hypothalamic cholinergic receptors may underlie aggressive behavior in humans exposed to cholinesterase inhibitors. A relationship between cholinesterase inhibitors and aggression has important implications for public health, raising the possibility of unappreciated neurotoxic influences on behavior.