A PET study of the noradrenergic system, gender differences and depression effects

Abstract

Purpose. This study is a PET examination of central noradrenergic function in depression and in healthy volunteers using the clonidine challenge test as a neuroendocrine probe. Method. All subjects were right-handed, not taking any medications, and non-smokers. The depressed female subjects were diagnosed by the Structured Clinical Interview for Diagnosis for DSM-IV criteria for major depression and by a clinical consultation. The severity of their depression was assessed with the 17-item Hamilton Depression Rating Scale (HRSD) with a minimum score of 18. Matched healthy female volunteers by age $\pm$2 years and phase in menstrual cycle were recruited, as well as healthy male volunteers. Subjects received a clonidine infusion of 1.4 $\mu$g/kg intravenously. For the female subjects, regional cerebral blood flow (rCBF) was measured with two scans at baseline and two scans following the clonidine infusion with H$\sb2\sp{15}$O using PET. For the male subjects, rCBF was measured with two scans at baseline and three scans following the clonidine infusion. During the scans, each subject's activity was standardized with a continuous performance task. (Abstract shortened by UMI.)