title: Cognitive behavior therapy in patients with chronic fatigue syndrome: the role of illness acceptance and neuroticism.
abstract: OBJECTIVE
  Increasing the quality of life (QoL) of patients with chronic fatigue is challenging because recovery is seldom achieved. Therefore, it is important to identify processes that improve QoL. This study examined the extent of improvement related to cognitive behavior group therapy (CBT), and whether improvement is affected by initial levels of acceptance and neuroticism.
  
  
  METHODS
  Eighty CFS patients followed CBT, and self-reported (pre-post design) on mental and physical QoL (MQoL and PQoL), fatigue, acceptance, and neuroticism. The extent of improvement was analyzed using t-tests, effect sizes, and clinically significant change criteria. Whether acceptance and neuroticism at baseline predicted changes was analyzed by means of correlation and regression analyses.
  
  
  RESULTS
  Significant improvement was found for all variables. The effect size for MQoL and PQoL was small; for acceptance and fatigue, effect size was moderate. About 20% (MQoL) to 40% (fatigue) of the participants clinically improved. Pre-treatment level of acceptance was negatively correlated with changes in MQoL, not with PQoL changes. Neuroticism pre-treatment was positively related with MQoL changes. Regression analysis showed an effect of acceptance on changes in MQoL beyond the effect of neuroticism.
  
  
  CONCLUSIONS
  Although CBT is an evidence-based treatment, the sizes of the effects are often small regarding QoL. Our study also revealed small effect sizes. Our study showed that patient characteristics at baseline were significantly associated with MQoL outcome; indicating that CFS patients with high neuroticism or with a low acceptance show more improvement in MQoL. We propose to specifically target acceptance and neuroticism before treatment in order to maximize clinical relevance.
authors.affiliation: Department of General Internal Medicine, Ghent University Hospital, Belgium. Carine.Poppe@ugent.be
authors.forename: Carine
authors.initials: C
authors.lastname: Poppe
authors.forename: Mirko
authors.initials: M
authors.lastname: Petrovic
authors.forename: Dirk
authors.initials: D
authors.lastname: Vogelaers
authors.forename: Geert
authors.initials: G
authors.lastname: Crombez
mesh_terms: D000223:Adaptation, Psychological; D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis / Q000523:psychology / Q000628:therapy*; D001519:Behavior; D015928:Cognitive Behavioral Therapy / Q000379:methods*; D003131:Combined Modality Therapy; D055317:Evidence-Based Practice; D015673:Fatigue Syndrome, Chronic / Q000175:diagnosis / Q000523:psychology / Q000628:therapy*; D005260:Female; D006801:Humans; D055809:Illness Behavior; D008297:Male; D008875:Middle Aged; D000075384:Neuroticism; D011615:Psychotherapy, Group / Q000379:methods*; D011788:Quality of Life / Q000523:psychology; D016896:Treatment Outcome