Prolactin and cortisol responses to the experience of low back pain.

Demographic, clinical and psychological characteristics of 92 patients with low back pain were correlated with prolactin and cortisol levels in cerebrospinal fluid (CSF). Somatization and depression scores correlated statistically significantly with the CSF serum ratio of prolactin both in men and in the total group. An increased CSF/serum ratio of cortisol was slightly associated with somatization scores in the total group. Multiple stepwise regression, furthermore, revealed that somatization, anxiety and one of the pain indices contributed to the variance in the CSF prolactin level, which was mostly dependent on the respective serum level. Sex and electromyographic findings (EMG) accounted for 12 and 7%, respectively, of the variance in the afternoon cortisol levels. Women reported more somatization and depression feelings than did men. Most of the data support our earlier assumption that male and female pain patients have different coping mechanisms. In spite of the common underlying endocrine responses to distress in men and women, gender differences in psychological response appear to modify endocrine responses to the experience of low back pain.