The effects of dietary tryptophan on affective disorders

Arch Psychiatr Nurs. 2015 Apr;29(2):102-7. doi: 10.1016/j.apnu.2014.11.008. Epub 2014 Dec 9.


Using a randomized crossover study design, 25 healthy young adults were examined for differences in anxiety, depression, and mood after consuming a high tryptophan and a low tryptophan diet for 4days each. There was a 2week washout between the diets. A within-subjects analysis of the participants' mood indicated significantly (p<.01) more positive affect scores after consuming a high tryptophan diet as compared to a low tryptophan diet. Negative affect differences between the diets were not statistically significant (p>.05). Also, consuming more dietary tryptophan resulted in (p<.05) less depressive symptoms and decreased anxiety.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Affect / drug effects*
  • Anxiety Disorders / diagnosis
  • Anxiety Disorders / diet therapy*
  • Anxiety Disorders / psychology
  • Cross-Over Studies
  • Depressive Disorder / diagnosis
  • Depressive Disorder / diet therapy*
  • Depressive Disorder / psychology
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Tryptophan / administration & dosage*
  • Young Adult


  • Tryptophan