Chronic fatigue syndrome beginning suddenly occurs seasonally over the year

The fact that many patients with chronic fatigue syndrome (CFS) have an infectiouslike sudden onset to their illness has led to the hypothesis that CFS is a medical illness. If CFS were, on the other hand, a psychiatric disorder related to symptom amplification, one would expect illness onset to occur randomly over the calendar year. This study tested that hypothesis with 69 CFS patients whose illness was on the more severe side of the illness spectrum; all patients reported sudden illness onset with the full syndrome of sore throat, fatigue/malaise, and diffuse achiness developing over no longer than a 2-day period. Date of illness onset was distinctly nonrandom. It peaked from November through January and was at its lowest from April through May. These data support the hypothesis that an infectious illness can trigger the onset of CFS. (Chronobiology International, 17(1), 95-99, 2000).

Chronic fatigue syndrome (CFS) is a medically unexplained illness characterized by fatigue, pain, and cognitive complaints. Because many of the symptoms of CFS overlap with those of depression, some argue that CFS is a somatic manifestation of depression or a somatoform disorder. Komaroff (1988) has suggested that, because CFS patients develop their illness suddenly with an infectiouslike presentation, this supports an underlying medical etiology to the illness. If CFS were indeed triggered by an infectious illness, one would expect to find the dates of sudden illness onset to occur more often in months when viral infections are common. If CFS were a somatoform disorder, one would expect a random distribution of dates of illness onset across the calendar year. Since our center has a large number of CFS patients who report a sudden infectiouslike illness onset, the purpose of this paper was to determine if the dates of illness onset occurred randomly or nonrandomly across the calendar year.