TFF2 and major depressive disorder: The aims of the current study were: 1) to establish the prevalence of pain and associated symptoms in premenopausal women with MDD compared to healthy controls; 2) to determine whether there is a relationship between pain intensity and the clinical features of depression; and 3) to examine the relationship of neuropeptides (Substance P (SP) and Calcitonin-Gene-Related-Peptide (CGRP)) to major depression.