Possible involvement of endorphin withdrawal or imbalance in specific premenstrual syndromes and postpartum depression.

Premenstrual and postpartum dysphoric changes are very prevalent. However, their etiology is still obscure. The authors hypothesize that changes in levels of endorphins may be involved in the pathophysiology of these changes. Studies of various endorphins indicate a possible relationship between levels of endorphins and depressive symptoms. In addition, some studies of naloxone and naltrexone suggest a relationship between a blockage in the action of endorphins and the development of a syndrome of dysphoric symptoms similar to the depressive features manifested premenstrually and postpartum by many women and frequently seen in some depressed outpatients. There is also some evidence that there may be a relationship between elevated levels of endorphins and other subtypes of depressive syndromes. Endorphins and estrogen levels have been shown to covary. During the postpartum and the premenstrual period, levels of both change rapidly and substantially. Therefore the link between changes in levels of endorphins and the dysphoric changes during the periods in focus is supported from three complementary directions: (1) the characteristic psychiatric symptomatology, (2) the reported hormonal changes, and (3) the possible involvement of endorphins in neuroendocrine regulation.