The cognitive behavioural model of chronic fatigue syndrome (CFS) suggests that the illness is caused through reciprocal interactions between physiology, cognition, emotion and behaviour. The purpose of this study was to investigate whether the psychological factors operationalized in this model could predict the onset of CFS following an acute episode of infectious mononucleosis commonly known as glandular fever (GF).

A total of 246 patients with GF were recruited into this prospective cohort study. Standardized self-report measures of perceived stress, perfectionism, somatization, mood, illness beliefs and behaviour were completed at the time of their acute illness. Follow-up questionnaires determined the incidence of new-onset chronic fatigue (CF) at 3 months and CFS at 6 months post-infection.

Of the participants, 9.4% met the criteria for CF at 3 months and 7.8% met the criteria for CFS at 6 months. Logistic regression revealed that factors proposed to predispose people to CFS including anxiety, depression, somatization and perfectionism were associated with new-onset CFS. Negative illness beliefs including perceiving GF to be a serious, distressing condition, that will last a long time and is uncontrollable, and responding to symptoms in an all-or-nothing behavioural pattern were also significant predictors. All-or-nothing behaviour was the most significant predictor of CFS at 6 months. Perceived stress and consistently limiting activity at the time of GF were not significantly associated with CFS.

The findings from this study provide support for the cognitive behavioural model and a good basis for developing prevention and early intervention strategies for CFS.