Is chronic pain a variant of depressive disease? The case of primary fibromyalgia syndrome.

The responses of 45 primary fibromyalgia syndrome (PFS) patients, 29 rheumatoid arthritis (RA) patients and 31 healthy non-pain controls (NC) on the Zung Self-Rating Depression scale were compared. No difference between the PFS and RA groups was found, although the former has no known organic pathology, unlike the latter. Therefore, the hypothesis that the presentation of chronic pain in the absence of a known organic pathology is a variant of 'depressive disease' was not supported in the case of PFS. However, a subgroup of PFS (28.6%) and RA (31.0%) patients appeared to be experiencing significant depressive symptomatology.