We have described three patients who illustrate the broad clinical spectrum of quinacrine-associated neuropsychiatric disturbances. The toxic manifestations range from subtle changes of restlessness, insomnia, hyperirritability to frank psychosis and seizures. These symptoms may follow only a few doses of the drug, or they may occur well after the drug has been discontinued. Our patients reemphasize the importance of recognizing the variability of quinacrine-induced toxic reactions.