1. ¹Eating Disorders Program, Douglas Hospital, Montreal, QC, Canada
2. ²Psychiatry Department, McGill University, Montreal, QC, Canada
3. ³Research Centre, Douglas Hospital, Montreal, QC, Canada
4. ⁴Department of Social and Preventive Medicine and Interdisciplinary Research Group on Health (GRIS), University of Montreal, Montreal, QC, Canada
5. ⁵Psychology Department, McGill University, Montreal, QC, Canada

Correspondence: Dr H Steiger, Eating Disorders Program, Douglas Hospital, 6875 LaSalle Blvd., Montreal (Verdun), QC, Canada H4H 1R3. Tel: +514 761 6131, ext. 2895; Fax: +514 888 4085; E-mail: stehow@douglas.mcgill.ca

Received 27 May 2005; Revised 14 November 2005; Accepted 15 November 2005; Published online 11 January 2006.

Abstract

Reduced brain serotonin (5-hydroxytryptamine: 5-HT) transporter activity has been associated with susceptibility to various forms of psychopathology, including bulimia nervosa (BN) and related syndromes characterized by appetitive or behavioural dysregulation. We applied density (B_max) of platelet [³H-]paroxetine binding as a proxy for central 5-HT reuptake activity in two groups of women (33 with BN-spectrum disorders and 19 with no apparent eating or psychiatric disorders), most of these individuals' mothers (31 and 18, respectively), and a small sampling of their sisters (seven and eight, respectively). Hierarchical linear modeling techniques were used to account for nesting of individuals within families and diagnostic groupings. Bulimic probands, their mothers, and their sisters all displayed significantly lower density (B_max) of platelet-paroxetine binding than did 'control' probands, mothers, or sisters—even when relatives showing apparent eating or psychiatric disturbances were excluded. In addition, in bulimic probands and mothers, significant within-family correlations were obtained on B_max. These findings imply a heritable trait (or endophenotype), linked to 5-HT activity, and carried by BN sufferers and their first-degree relatives (even when asymptomatic). We propose that, under conducive circumstances, such a trait may increase risk of binge-eating behavior, or associated symptoms of affective or behavioral dysregulation.