Complex sentence: The name comes from their primary effect of inducing a medical state of frank delirium, characterized by stupor, utter confusion, confabulation, and regression to "phantom" behaviors such as disrobing and plucking.
Split into simpler sentences: The name comes from their primary effect of inducing a medical state of frank delirium. The delirium produced is characterized by stupor, utter confusion, confabulation, and regression to "phantom" behaviors such as disrobing and plucking.