Serum levels of excitatory amino acids, serine, glycine, histidine, threonine, taurine, alanine and arginine in treatment-resistant depression: modulation by treatment with antidepressants and prediction of clinical responsivity

Acta Psychiatr Scand. 1998 Apr;97(4):302-8. doi: 10.1111/j.1600-0447.1998.tb10004.x.


Previous research has revealed that major depression is accompanied by disorders in excitatory amino acids, e.g. glutamate and aspartate, and alterations in serum levels of other amino acids, e.g. serine, glycine and taurine. The aim of the present study was to examine serum levels of aspartate, asparagine, glutamate, glutamine, serine, glycine, threonine, histidine, alanine, taurine and arginine in major depression patients with treatment-resistant depression (TRD). No significant differences in the serum concentrations of any of the above amino acids could be found between patients with and without TRD and normal controls. Non-responders to treatment with antidepressants during a period of 5 weeks were characterized by significantly lower serum levels of aspartate, asparagine, serine, threonine and taurine. A 5-week period of treatment with antidepressants significantly reduced the serum levels of aspartate, glutamate and taurine, and significantly increased the serum concentrations of glutamine. The results suggest that alterations in serum levels of aspartate, asparagine, serine, threonine and taurine may predict the subsequent response to treatment with antidepressants, and that the latter may modulate serum levels of excitatory amino acids and taurine.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Alanine / blood
  • Antidepressive Agents / adverse effects
  • Antidepressive Agents / therapeutic use*
  • Antidepressive Agents, Tricyclic / adverse effects
  • Antidepressive Agents, Tricyclic / therapeutic use
  • Arginine / blood
  • Asparagine / blood
  • Aspartic Acid / blood
  • Depressive Disorder, Major / blood
  • Depressive Disorder, Major / drug therapy*
  • Depressive Disorder, Major / psychology
  • Drug Resistance
  • Drug Therapy, Combination
  • Excitatory Amino Acids / blood*
  • Female
  • Fluoxetine / adverse effects
  • Fluoxetine / therapeutic use
  • Glycine / blood
  • Histidine / blood
  • Humans
  • Male
  • Middle Aged
  • Personality Inventory
  • Pindolol / adverse effects
  • Pindolol / therapeutic use
  • Prognosis
  • Selective Serotonin Reuptake Inhibitors / adverse effects
  • Selective Serotonin Reuptake Inhibitors / therapeutic use
  • Serine / blood
  • Taurine / blood
  • Threonine / blood
  • Trazodone / adverse effects
  • Trazodone / therapeutic use
  • Treatment Outcome


  • Antidepressive Agents
  • Antidepressive Agents, Tricyclic
  • Excitatory Amino Acids
  • Serotonin Uptake Inhibitors
  • Fluoxetine
  • Taurine
  • Threonine
  • Aspartic Acid
  • Serine
  • Histidine
  • Asparagine
  • Arginine
  • Pindolol
  • Alanine
  • Glycine
  • Trazodone