[Clin Psychol Sci Prac 18: 325–330, 2011]
The meta-analytic review of Castell, Kazantzis, and Moss-Morris (2011) is a valuable contribution to the debate about the efficacy of behavioral interventions for chronic fatigue syndrome (CFS). Again it is found that cognitive behavior therapy (CBT) has a positive effect on the outcomes of patients with CFS. However, a substantial number of patients do not profit (enough) from this intervention. Increasing our knowledge about the mechanisms of change and other relevant aspects related to the treatment response could help to improve further the efficacy and applicability of CBT for CFS. This commentary discusses some of these aspects and, where possible, research strategies are proposed.