Bimodal distribution of serum trypotphan level.

Serum levels of total L-tryptophan (L-TP) were determined before and during treatment in patients suffering from endogenous depression, who were treated with L-TP, 6 g daily, and unilateral electroconvulsive therapy (ECT). The gaussian curve of initial L-TP concentrations changed into a bimodal distribution during treatment. The patients with initially lower L-TP levels also had lower L-TP levels during the treatment, thus forming the low-concentration group within the bimodal distribution.

Has tryptophan any anticonvulsive effect?

In an an intra-individual crossover trial depressed patients were treated with the 5-hydroxytryptamine (5-HT) precursor L-tryptophan (L-TP) and unilateral ECT, or with unilateral ECT alone. The oral dose of L-TP was 6 g the day before ECT and 3 g on the day of ECT, 4 hours before the treatment. The seizure duration was measured on EEG records.

L-tryptophan and 5-hydroxytryptophan in the treatment of depression. A review.

Trials performed do not provide evidence for an antidepressant effect of 5-HTP. L-TP, without interacting pharmaca, does not appear to be a well-documented antidepressant. The only convincing evidence for L-TP as an antidepressant is that L-TP enhances the effect of MAOI.