CSF monoamine metabolites in chronic pain.

Metabolites of selected neurotransmitters (5-HIAA, HVA and DOPAC) and beta-endorphin were measured in the CSF of 39 chronic pain patients and compared to controls. Twelve of the pain patients also fulfilled criteria for major depression. The concentration of 5-HIAA was increased in female but not male pain patients; there was no significant difference in the CSF concentrations of HVA and DOPAC. The presence of depression did not influence the concentrations of neurotransmitters. No correlation was found between the concentrations of monoamine metabolites and beta-endorphin. However, there was a positive correlation between 5-HIAA and HVA in controls and chronic pain patients without depression but not in depressed patients. It is concluded: chronic pain states are associated with elevation of CSF 5-HIAA in female patients; depression abolishes a positive correlation between 5-HIAA and HVA.