1 Eating Disorders Continuum and Research Center, Douglas Mental Health University Institute, Montreal, QC, Canada.
2 Department of Psychology, Concordia University, Montreal, QC, Canada.
3 Department of Molecular Biology, Semmelweis University, Budapest, Hungary.
4 Department of Psychiatry, McGill University, Montreal, QC, Canada.

Introduction: Eating disorders are characterized by maladaptive eating behaviors and preoccupations around body shape, weight, and eating. The serotonin system has been among the most widely studied neurobiological factors in relation to eating disorders. Recent research also highlighted the role of oxytocin.

Aims and methods: This article aims to review animal and human studies on the involvement of central serotonin and oxytocin, and their interplay in eating disorders in particular. We synthesize results from studies using animal models of eating disorders and from research conducted in healthy individuals and clinical populations.

Results/outcomes: Altered serotonin neurotransmission and oxytocin levels in the brain-particularly in the hypothalamus, brainstem, and limbic regions-were associated with disturbances in eating behaviors and related maladaptive cognitions and emotions. These brain regions were found to constitute a typical neural network through which both central serotonin and oxytocin might operate in a bidirectional manner.

Conclusions/interpretation: Based on the preceding findings, we describe a developmental biopsychosocial model relevant to eating disorders, including the role of serotonin-oxytocin interactions in the brain. While it is clear that eating disorders are multifactorial in which many biopsychosocial pathways are involved, the current review highlights the importance of well-designed translational research when studying mechanisms of serotonin-oxytocin interactions in the brain. Such research would help to better understand the effects of joint central oxytocin and serotonin administration as a possible preventive or therapeutic intervention for eating disorders.