Prins et al (2005) assessed psychiatric comorbidity in chronic fatigue syndrome (CFS) using the Structured Clinical Interview for DSM–III–R. Comorbidity was remarkably low compared with similar investigations, and in particular the apparent absence of current post-traumatic stress disorder (PTSD) was striking. The authors speculated that the low comorbidity rates might result mainly from a lack of ‘psychiatric bias’ of the examiners. They also found that psychiatric comorbidity did not predict the outcome of cognitive–behavioural therapy.
You can read the rest of this comment here: http://bjp.rcpsych.org/content/188/4/395.2.long
Source: Van Houdenhove B. Psychiatric comorbidity and chronic fatigue syndrome. Br J Psychiatry. 2006 Apr;188:395; author reply 396. http://bjp.rcpsych.org/content/188/4/395.2.long (Full article)