A population-based study of chronic fatigue syndrome (CFS) experienced in
differing patient groups: An effort to replicate Vercoulen et al.'s model
of CFS

Journal of Mental Health,14(3), June 2005, pp. 277-289

Sharon Song and Leonard A Jason

DePaul University, Chicago, Illinois, USA


Abstract:

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.

Keywords: CFS, physical activity, replication, psychiatrically-explained
fatigue