Sex Differences in Plasma Prolactin Response to Tryptophan in Chronic Fatigue Syndrome Patients With and Without Comorbid Fibromyalgia

Abstract

These results indicate that women with CFS alone have upregulated serotonergic tone that is not seen in those with comorbid FM. The lack of effect in men suggests a mechanism that might explain, in part, the increased prevalence of CFS in women. The data support the interpretation that CFS in women is a different illness from FM.