Brain Allergies and the Psychonutrient Connection

There's a very good OLD book called "Brain Allergies" by W. Philpot that explains how to be cured from schizophrenia by diet and other things like killing parasites.

http://www.amazon.com/Brain-Allergies-Psychonutrient-Connection-Including/dp/...

It made a lot of sense and the newer versions are never as good! Why is that???