Previous reviews have consistently highlighted the highly variable (and contradictory) prevalence rates with different instruments to measure ON, lack of stable factor structure and psychometrics across ON measures, paucity of data on ON in clinical samples, and a need for a modern re-conceptualization of ON. The diagnosis of ON is challenging as it likely spans a spectrum from "normal" to "abnormal," and "functional" to "dysfunctional." "Non-pathological" orthorexia is not related to psychopathological constructs in the same way that ON is.