Serotonin neurotransmission in anorexia nervosa

Behav Pharmacol. 2012 Sep;23(5-6):478-95. doi: 10.1097/FBP.0b013e328357440d.


Patients with anorexia nervosa (AN) show extreme dieting weight loss, hyperactivity, depression/anxiety, self-control, and behavioral impulsivity. 5-Hydroxytryptamine (5-HT; serotonin) is involved in almost all the behavioral changes observed in AN patients. Both genetic and environmental factors contribute toward the pathogenesis of AN. It is a frequent disorder among adolescent girls and young women and starts as an attempt to lose weight to look beautiful and attractive. Failure to see the turning point when fasting becomes unreasonable leads to malnutrition and AN. Tryptophan, the precursor of serotonin and an essential amino acid, is only available in the diet. It is therefore likely that excessive diet restriction and malnutrition decrease brain serotonin stores because the precursor is less available to the rate-limiting enzyme of 5-HT biosynthesis, which normally exists unsaturated with its substrate. Evidence shows that diet restriction-induced exaggerated feedback control over 5-HT synthesis and the smaller availability of tryptophan decreases serotonin neurotransmission at postsynaptic sites, leading to hyperactivity, depression, and behavioral impulsivity. A compensatory upregulation of postsynaptic 5-HT-1A receptors and hypophagic serotonin receptors may be involved in anxiety and suppression of appetite. It is suggested that tryptophan supplementation may improve pharmacotherapy in AN.

Publication types

  • Review

MeSH terms

  • Animals
  • Anorexia Nervosa / diet therapy
  • Anorexia Nervosa / drug therapy
  • Anorexia Nervosa / metabolism*
  • Anorexia Nervosa / psychology
  • Anxiety / etiology
  • Anxiety / prevention & control
  • Anxiety / psychology
  • Appetite Depressants / adverse effects
  • Appetite Depressants / pharmacology
  • Appetite Depressants / therapeutic use
  • Appetite Regulation / drug effects
  • Combined Modality Therapy
  • Depression / etiology
  • Depression / prevention & control
  • Depression / psychology
  • Diet* / adverse effects
  • Diet* / psychology
  • Disease Models, Animal
  • Disease Susceptibility
  • Disruptive, Impulse Control, and Conduct Disorders / diet therapy
  • Disruptive, Impulse Control, and Conduct Disorders / drug therapy
  • Disruptive, Impulse Control, and Conduct Disorders / metabolism
  • Disruptive, Impulse Control, and Conduct Disorders / psychology
  • Female
  • Humans
  • Male
  • Malnutrition / etiology
  • Malnutrition / prevention & control
  • Malnutrition / psychology
  • Serotonin / metabolism*
  • Sex Characteristics
  • Synaptic Transmission* / drug effects


  • Appetite Depressants
  • Serotonin