Prolactin response to fentanyl in depression

Ten unmedicated female inpatients with major depression (DSM-III) and 10 healthy volunteer women were given an intravenous injection of 0.1 mg fentanyl at 9:00 am and 9:00 pm on different days. The prolactin secretory response to this opioid agonist was investigated for 1 h with serial blood sampling. Repeated measures Analysis of Variance yielded a significant effect offentanyl administration on prolactin secretion ( p < 0.0001), and there were elevated hormone responses in the evening ( p< 0.005). No group difference was seen between healthy volunteers and depressed patients, but four of the depressives showed the most blunted response, and three of these low responders committed suicide within I year.