Prolactin and cortisol in cerebrospinal fluid: sex-related associations with clinical and psychological characteristics of patients with low back pain

Clinical and psychological characteristics of 33 patients with low back pain were correlated with prolactin and cortisol concentrations in cerebrospinal fluid (CSF). A significant sex difference was found in CSF prolactin levels: women secreted more prolactin into the CSF than did men. High CSF cortisol levels were associated with a rhizographically-demonstrable abnormality, suggesting a relationship between cortisol and an 'organic' origin of pain symptoms. Impairment-disability indices also were associated with CSF hormone levels. Moreover, the two hormones had dissociated psychological correlates. Prolactin was related to depression and anxiety, whereas cortisol was related to somatization. Sex differences were observed in the cortisol response to the symptoms of chronic low back pain, especially in the presence of anxiety and somatization. The sex differences in psychoneuroendocrine and emotional responses suggest that male and female pain patients have different coping mechanisms.