Association Between Decreased Serum Tryptophan Concentrations and Depressive Symptoms in Cancer Patients Undergoing Cytokine Therapy

The present study aimed at assessing the relationship between serum concentrations of the amino acids tryptophan & tyrosine, major precursors of serotonin & norepinephrine respectively, & depressive symptoms in cancer patients undergoing cytokine therapy. The development & severity of depressive symptoms, especially anorexia, pessimistic thoughts, suicidal ideation & loss of concentration were positively correlated with the magnitude of the decreases in tryptophan concentrations during treatment. (47 refs)