title: Does the heterogeneity of chronic fatigue syndrome moderate the response to cognitive behaviour therapy? An exploratory study.
abstract: BACKGROUND
  Chronic fatigue syndrome (CFS) is a heterogeneous condition. A few studies have shown that some independent factors predict outcomes after cognitive behaviour therapy (CBT). Two recent systematic reviews suggest that heterogeneity may moderate treatment outcomes. However, no study has explored whether subgroups of CFS predict response to treatment.
  
  
  METHODS
  We used both latent class analysis (LCA) and latent class regression (LCR) to clarify the relationship between subgroups of CFS patients (n = 236), diagnosed using the Oxford diagnostic criteria, and the response to CBT. We measured symptoms, demographics, mood, and cognitive and behavioural responses to illness to define subgroups.
  
  
  RESULTS
  We found 5 latent classes by LCA, which did not differ in the direction of their response to CBT, with all classes showing improvement. In contrast, an exploratory LCR identified 4 latent classes, 1 of which predicted a poor response to CBT, whereas the other 3 predicted a good outcome, accounting for more than 70% of the patients. The negative outcome class was defined by weight fluctuations and physical shakiness, anxiety, pain and being focused on symptoms.
  
  
  CONCLUSIONS
  CBT should be offered to all classes of patients with CFS, when defined by these measures. It may be possible to predict a minority group with a negative outcome, but this exploratory work needs replication.
authors.affiliation: Department of Psychological Medicine, Institute of Psychiatry, King's College London, UK. matteo.cella@kcl.ac.uk
authors.forename: Matteo
authors.initials: M
authors.lastname: Cella
authors.forename: Trudie
authors.initials: T
authors.lastname: Chalder
authors.forename: Peter D
authors.initials: PD
authors.lastname: White
mesh_terms: D000328:Adult; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D015673:Fatigue Syndrome, Chronic / Q000145:classification* / Q000175:diagnosis / Q000628:therapy*; D005260:Female; D006801:Humans; D008297:Male; D010865:Pilot Projects; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D016896:Treatment Outcome