SUDDEN VS GRADUAL ONSET OF CHRONIC-FATIGUE-SYNDROME DIFFERENTIATES INDIVIDUALS ON COGNITIVE AND PSYCHIATRIC MEASURES

To examine the influence of mode of illness onset on psychiatric statu s and neuropsychological performance, 36 patients with CFS were divide d into two groups: sudden vs gradual onset of symptoms. These two CFS subgroups were compared to each other and to sedentary healthy control s on standardized neuropsychological tests of attention/concentration, information processing efficiency, memory, and higher cortical functi ons. In addition, the distribution of comorbid Axis I psychiatric dise ase between the two CFS groups was examined. The rate of concurrent ps ychiatric disease was significantly greater in the CFS-gradual group r elative to the CFS-sudden group. While both CFS groups showed a signif icant reduction in information processing ability relative to controls , impairment in memory was more severe in the CFS-sudden group. Becaus e of the significant heterogeneity of the CFS population, the need for subgroup analysis is discussed. (C) 1997 Elsevier Science.