THE FLESINOXAN 5-HT1A RECEPTOR CHALLENGE IN MAJOR DEPRESSION AND SUICIDAL-BEHAVIOR

The prevailing neurochemical theory about biological correlates of sui cidal behavior focuses on the serotonergic system. In this study, we a ssessed the cortisol, ACTH, CH, prolactin and temperature responses to flesinoxan, a5-HT1A agonist, in 30 DSM-III-R major depressed inpatien ts subgrouped into suicide attempters (n = 15) and nonattempters (n = 15). The patients were assessed after a drug-free period of at least 3 weeks. A subsample of 16 patients completed the Buss-Durkee Hostility Inventory as a measure of impulsive aggressive behavior. Mean delta c ortisol responses to flesinoxan were significantly lower in the group of depressed patients with a history of suicide attempts than in the g roup without history of suicidal behavior: for the delta cortisol valu es 14.5 +/- 16.3 mu g/l vs 101 +/- 94 mu g/l (F = 8.9, df = 5.25, p = 0.006). There was also a very significant difference between suicide a ttempters and nonattempters for the temperature (delta T degrees) resp onses to flesinoxan: 0.20 +/- 0.24 degrees C vs 0.60 +/- 0.24 degrees C (F = 18.1, df = 5.25, p = 0.0003). Hormonal and temperature response s to flesinoxan were not correlated with BDHI irritability or assault subscale scores. The results of the present study support the implicat ion of the serotonergic system, particularly 5-HT1A receptors, in the control of self-directed aggressive behavior. Moreover, in depressed p atients, serotonergic abnormalities do not appear to be related to agg ressive behavior.