Fenfluramine challenge in anxious children

The study objective was to determine if serotonergic challenge with oral ra cemic fenfluramine would differentiate between childhood anxiety disorders in comparison to normal controls. Subjects were 24 children with anxiety di agnoses (DSM-IIIR) by structured interview, and 14 normal controls (ages 7- 14 years) matched for age and sex. All subjects were given a standard chall enge dose of d,1-fenfluramine (1 mg/kg) followed by serial assessments of c ardiovascular, neurohormonal, and mood parameters over a five hour period. In response to fenfluramine. controls demonstrated increases in subjective anxiety and systolic blood pressure relative to anxious subjects. Fenfluram ine was safely tolerated and did not induce panic symptoms in any subject. Exaggerated prolactin response to fenfluramine differentiated an obsessive- compulsive disorder (OCD) subset from both controls and other anxiety disor ders. Fenfluramine challenge differentiates anxious children from healthy c ontrols by elevated anxiety ratings and systolic blood pressure in controls . Increased prolactin response to fenfluramine discriminates children with obsessive-compulsive disorder from both healthy children and children with other anxiety diagnoses. As adults with OCD appear to demonstrate a blunted prolactin response to fenfluramine challenge, the serotonin pathways invol ved may differ between 'early' and 'late' onset disorder, or the serotonin substrates tapped by this challenge may change over time. Copyright (C) 200 0 John Wiley & Sons, Ltd.