which of the following is a true statement if the lethal dose of a psychoactive drug is high we cannot reliably compute the drugs effective dose be if the lethal dose of a psychoactive drug is low we cannot really compute the drugs therapatic ratio see if the effective dose of a psychoactive drug is not established we cannot really compute the drugs legal dose if the lethal dose of a psychoactive drug is not established we cannot reliably compute the drugs therapeutic ratio which is the right answer