Let us not forget that this class of drugs (which includes diphenhydramine (Benadryl), scopolamine, and datura is called "deliriant".
From Wikipedia: " The term was introduced by David F. Duncan and Robert S. Gold to distinguish these drugs from psychedelics and dissociatives, such as LSD and ketamine respectively, due to their primary effect of causing delirium, as opposed to the more lucid states produced by other hallucinogens (psychedelics and dissociatives)... The delirium produced is characterized by stupor, confusion, confabulation, and regression to "phantom" behaviors such as disrobing and plucking.[2] Other commonly reported behaviors include holding full conversations with imagined people, finishing a complex, multi-stage action (such as getting dressed) and then suddenly discovering one had not even begun yet, and being unable to recognize one's own reflection in a mirror."
This is the expected behavior for someone who consumes about 500-700mg of diphenhydramine at once (the dose suggested on the package is usually 50mg). Benadryl is probably the most powerful hallucinogen known; it distorts the senses far more than even some of the most notorious illegal drugs and the reasons for its continued over-the-counter legality might make for an interesting book. Obviously it has healthy uses, and many deliriants have long-established religious uses in North America. The Serpent and the Rainbow and Passage of Darkness: The Ethnobiology of the Haitian Zombie are two books that explain how anticholinergic drugs are what create real-life zombies.