A fixed, false system of beliefs with complex logical structure, constructed in order to protect the coherence of a single central delusion.
Example: The patient relates an elaborate tale of persecution spanning more than 20 years, incorporating numerous details that fit together perfectly.
Grinnell, R. (2011). Systematized Delusion. Psych Central. Retrieved on February 14, 2016, from http://psychcentral.com/encyclopedia/systematized-delusion/