myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS). Current case
definitions differ in the number and types of symptoms required. This ambiguity impedes the
search for biological markers and effective treatments. Purpose: This study sought to
empirically operationalize symptom criteria and identify which symptoms best characterize
the illness. Methods: Patients (n= 236) and controls (n= 86) completed the DePaul Symptom …