Reduced blood albumin, which binds tryptophan, is likely the most significant mechanism leading to decreased tryptophan in moderately chronic inflammatory diseases (such as depression and schizophrenia; McMenamy and Oncley, 1958; Yuwiler et al., 1977; Maes et al., 1991, 1996, 1997). This evidence concerns the gene ALB and schizophrenia.