Plasma levels of beta-endorphin in depressed patients with and without pain.

We studied 27 patients who complained of pain, for which no organic basis could be found, and 11 patients without pain. All patients were depressed according to clinical diagnosis and Beck Depression Inventory (BDI) scores. Plasma beta-endorphin levels were found not to differ between the two groups or across other variables. The patients who complained of pain had significantly higher scores on the BDI.