5-HIAA and HVA in CSF in patients with idiopathic pain disorders

Patients with idiopathic pain syndromes were compared with healthy volunteers and with patients suffering from chronic pain syndromes of neurogenic origin, with respect to the concentrations of the metabolites 5-hydroxy-indole-acetic acid (5-HIAA) and homovanillic acid (HVA) in cerebrospinal fluid (CSF). Patients with idiopathic pain syndromes were subdivided according to the presence or absence of somatic lesions. It was found that these groups did not differ in concentrations of 5-HIAA or HVA, at least not when values were corrected for age, sex, and body height. Patients with idiopathic pain syndromes were found to have low concentrations of 5-HIAA, but not of HVA, in CSF. These differences were also obvious when the values were corrected for age, sex, and body height. As low concentrations of 5-HIAA in CSF have previously been demonstrated in patients with depressive disorders, our results support the suggestion by Blumer and Heilbronn (1982) that the idiopathic pain syndrome is a variant of depressive disease. At least the two syndromes share a common pathogenetic mechanism—a disturbance in serotonergic turnover.