HIGH DELTA-SLEEP-INDUCING PEPTIDE-LIKE IMMUNOREACTIVITY IN PLASMA IN SUICIDAL PATIENTS WITH MAJOR DEPRESSIVE DISORDER

Background: Delta sleep-inducing peptide (DSIP) supposedly involves th e hypothalamus-pituitary-adrenal (HPA) axis. Previous studies have sho wn deviated plasma DSIP-like immunoreactivity (DSIP-LI) levels, as wel l as abnormal DSIP-LIW responses to corticotropin-releasing hormone in patients with major depressive disorder (MDD). This study was perform ed to investigate plasma-DSIP-LI and its association with the dexameth asone suppression test (DST) in suicide attempters. Methods: Plasma-DS IP and serum cortisol were measured before and after dexamethasone int ake in 34 suicide attempters and in healthy age-and sex-matched contro ls. Results: We Sound significantly elevated DSIP-LI levels in MDD pat ients (p < .005), and a significant correlation between predexamethaso ne cortisol and predexamethasone DSIP-LI levels in healthy controls, P ostdexamethasone DSIP-LI levels increased in subjects with low predexa methasone DSIP-LI levels, whereas they decreased in subjects with high predexamethasone DSIP-LI levels. Conclusions: Results give some suppo rt to the theory of glucocorticoid involvement in the regulation of DS IP, and suggest altered DSIP-LI levels in suicidal MDD patients. (C) 1 998 Society of Biological Psychiatry.