Plasma tryptophan levels and plasma tryptophan/ neutral amino acids ratio in patients with mood disorder, patients with obsessive-compulsive disorder, and normal subjects

Adelio Lucca, Valentina Lucini, Elisabetta Piatti, Paolo Ronchi, Enrico Smeraldi

Research output: Contribution to journalArticlepeer-review

Abstract

Fasting plasma trytophan (TRP) levels and ratios of total plasma tryptophan to the sum of five large neutral amino acids (LNAAs)-tyrosine, phenylalanine, leucine, isoleucine, and valine-that compete with trytophan for passage across the blood-brain barrier were found to be significantly lower in a group of 28 patients with major depression compared with 29 normal subjects and 21 patients with obsessive-compulsive disorder (OCD). The OCD group was divided in two subgroups: Patients with OCD alone and patients with a codiagnosis of major depression. Since it has been considered that these biological parameters reflect brain tryptophan and serotonin levels, our results suggest their importance in relation to the presence or absence of depressive symptoms. The values of the other LNAAs and their sum did not differ significantly among the groups.

Original languageEnglish
Pages (from-to)85-91
Number of pages7
JournalPsychiatry Research
Volume44
Issue number2
DOIs
Publication statusPublished - 1992

Keywords

  • Affective disorder
  • isoleucine
  • leucine
  • phenylalanine
  • serotonin
  • tyrosine
  • valine

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Biological Psychiatry
  • Psychology(all)

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