Mood- and restraint-based antecedents to binge episodes in bulimia nervosa: possible influences of the serotonin system

Background. In bulimic syndromes, binge episodes are thought to be caused by dietary restraint and negative moods. However, as central serotonin (5-hydroxytryptamine: 5-HT) mechanisms regulate appetite and mood, the 5-HT system could be implicated in diet- and mood-based binge antecedents. Method. We used hand-held computers to obtain repeated 'online' measurements of eating behaviors, moods, and self-concepts in 21 women with bulimic syndromes, and modeled 5-HT system activity with a measure of platelet [H-3]paroxetine-binding density. Results. Mood and self-concept ratings were found to be worse before binge episodes (than at other moments), and cognitive restraint was increased. After binges, mood and self-concept deteriorated further, and thoughts of dieting became more intense. Intriguingly, lower paroxetine-binding density predicted poorer mood and self-concept before a binge, larger post-binge decrements in mood and self-concept, and larger post-binge increases in dietary restraint. Conclusions. Paroxetine binding thus seemed to reflect processes that impacted upon mood-related antecedents to binge episodes, and consequences implicating mood and dietary restraint.