Objective: To evaluate the natural history of chronic fatigue syndrome (CFS) in a severely ill group of patients at three points in time.
Design: Patients were enrolled from April 1992 to February 1994 and were evaluated three times. Time 1 (at enrollment): history, physical evaluation, and psychiatric evaluation; Time 2 (median = 1.6yrs after initial evaluation): postal questionnaire to assess current condition; Time 3 (median = 1.8 yrs after Time 2): medical and psychiatric evaluations.
Setting: The New Jersey CFS Cooperative Research Center, an ambulatory setting.
Patients: Twenty-three patients fulfilled the 1988 case definition for CFS and had symptom complaints that were substantial or worse in severity. All patients were ill less than 4.5 years; and none had a DSM-III-R psychiatric disorder in the 5 years before illness onset; none had substance abuse in the 10 years before enrollment.
Main outcome measures: Severity of CFS symptoms was assessed by self-report questionnaires, laboratory tests, and medical examination. Psychological status was assessed using the Q-D15 and the Centers for Epidemiological Study-Depression Scale. At each time of evaluation, patients were categorized as severe, slightly improved, improved, and recovered.
Results: Over the 4 years of the study, 13 patients remained severely ill, 9 improved but still fulfilled the 1994 case definition for CFS, and 1 recovered. Illness duration, mode of onset, psychiatric status or depressed mood at intake, or chemical sensitivity did not predict illness outcome. One patient was diagnosed with an alternate illness, but it probably did not explain her CFS symptoms. Mood improved for those patients whose illness lessened.
Conclusions: The prognosis for recovery was extremely poor for the severely ill subset of CFS patients. The majority showed no symptom improvement and only 4% of the patients recovered. Illness severity between Times 2 and 3 remained stable.