A rating scale for fibromyalgia and chronic fatigue syndrome (the FibroFatigue scale).

Objective: To construct an observer's rating scale sensitive to change for measuring severity and treatment outcome in fibromyalgia (FM) and chronic fatigue syndrome (CFS) patients.

Methods: A selection of items from the Comprehensive Psychopathological Rating Scale (CPRS) were repeatedly rated and used as outcome measure of a 24-week treatment study. In the study 100 women, fulfilling the criteria for both FM and CFS, received intermittent injections of a staphylococcus toxoid or placebo.