Tryptophan catabolites and depression in the general population: results from the Gutenberg Health Study

Previous studies reported significantly altered tryptophan catabolite concentrations in major depression. Thus, tryptophan catabolites were considered as potential biomarkers of depression and their modulators as potential targets for psychopharmacotherapy. However, the results were based mainly on studies with small sample sizes limiting their generalizability. Against this background, we investigated the relationship of peripheral tryptophan catabolites with depression in a population-based sample with n = 3,389 participants (with fasting status ≥ 8 h and C-reactive protein