Background: Vercoulen et al.'s (1998) model characterizes patients with Chronic Fatigue Syndrome (CFS) as having insufficient motivation for physical activity or recovery, lacking an internal locus of control, and maintaining a self-defeating preoccupation with symptoms. However, this model has only been tested in a poorly specified group using a single comparison sample.
Aims: To investigate whether Vercoulen et al.'s model provides an adequate description of CFS in a community-based sample.
Method: A community-based sample recruited through telephone interviewing (N = 28,763) produced five groups (CFS, CF-psychiatrically-explained symptoms, CF-medically-unexplained symptoms, CF-substance misuse, and idiopathic CF). The data were analysed using path analysis with the endogenous (dependent) variables, fatigue severity, physical activity, and impairment, were ratio-level measurements and consisted of at least four values. The exogenous (independent) variables except for causal attribution of fatigue were also ratio-level measurements.
Results: The current investigation found that the Vercoulen et al. model adequately represented chronic fatigue secondary to psychiatric conditions but not CFS.
Conclusions: This finding points to important differences between CFS and psychiatrically-explained chronic fatigue which may have an impact on the development of therapy as well as explanatory models.
Declaration of interest: Financial support for this article was provided by the National Institutes of Allergies and Infectious Diseases grant number AI36295. There are no financial relationships that pose a conflict of interest.
Source: Journal of Mental Health, Volume 14, Issue 3, June 2005, pages 277–289; DOI: 10.1080/09638230500076165, by Song S, Jason LA. DePaul University, Chicago, Illinois, USA.