Ž . Psychiatry Research 81 1998 3138 Ipsapirone neuroendocrine challenge: relationship to aggression as measured in the human laboratory F. Gerard Moeller , Terry Allen, Don R. Cherek, Donald M. Dougherty, Scott Lane, Alan C. Swann Human Psychopharmacology Laboratory, Department of Psychiatry and Beha ioral Sciences, Uni ersity of Texas Houston Health Science Center, 1300 Moursund, Houston, TX 77030, USA Received 19 March 1998; received in revised form 18 June 1998; accepted 28 June 1998 Abstract Thirty-one human subjects were administered a neuroendocrine challenge with the 5-HT agonist ipsapirone after 1a Ž . completing six sessions of a laboratory measure of aggression, the Point Subtraction Aggression Paradigm PSAP , in order to determine if a laboratory measure of aggression was related to serotonin function. Subjects who showed Ž . more aggressive responding on the PSAP n 11 had a significantly blunted temperature response to ipsapirone Ž . compared to those with less aggressive responding n 20 . There was no difference between the two groups on the cortisol response to ipsapirone. This study supports a relationship between serotonin function and aggression as measured in the human laboratory, similar to the well-documented association between self-reported aggression and serotonin. 1998 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Serotonin; Cortisol; Temperature; Substance abuse 1. Introduction A number of studies examining the biology of human aggression find evidence for decreased Ž . serotonin 5-HT function in violent individuals. Some of these studies measured levels of the Corresponding author. Tel.: 1 713 5002858; fax: 1 713 5002618; e-mail: moeller@msi13.msi.uth.tmc.edu serotonin metabolite 5-hydroxyindolacetic acid Ž . 5-HIAA in CSF and found that individuals with a history of violent behavior had lower 5-HIAA Ž than individuals without such a history Brown et al., 1979; Linnoila et al., 1983; Virkkunen et al., . 1987 . Other studies have used the neuroen- docrine challenge as a measure of 5-HT function. Using the 5-HT agonist meta-chlorophenyl- 2c Ž . piperazine mCPP , Buydens-Branchey et al. Ž . 1997a found a blunted cortisol response in ag- 0165-178198$ - see front matter 1998 Elsevier Science Ireland Ltd. All rights reserved. Ž . PII S0165-1781 98 00081-X