Evaluation of the combination of tryptophan and ECT in the treatment of depression

Serum levels of total L‐tryptophan (L‐TP) were determined in patients suffering from endogenous depression, randomly assigned to two groups, one treated with L‐TP (6 g daily) and unilateral ECT, the other with placebo and unilateral ECT. L‐TP treatment was initiated at least 1 day before the first ECT and terminated 4 days after the last ECT. The degree of amelioration in depressive symptomatology was measured by doctors', nurses' and patients' rating scales. There was a close similarity in the levels of L‐TP concentration in the two groups before treatment (mean values 1.27 mg% and 1.28 mg%). ECT seems not to alter the serum L‐TP levels, judging from the values before and during treatment in the placebo group. During treatment, there was, as expected, a considerably higher L‐TP concentration in the L‐TP group (mean value 4.01 mg%). The L‐TP concentrations were bimodally distributed in the L‐TP group. This bimodality was not correlated to clinical variables. No relationship could be found between pretreatment L‐TP levels and depressive symptomatology. No evidence is therefore obtained that L‐TP levels are a pathogenic factor. There was no correlation between initial L‐TP levels and residual symptomatology 4 days and 1 month after the last ECT. Thus the L‐TP levels before treatment seem not to be of value in predicting “responders” to L‐TP treatment combined with ECT or to ECT alone. The levels of L‐TP during the treatment with L‐TP and ECT showed no relationship to residual symptomatology after the treatment. Thus the L‐TP levels do not seem to have a therapeutic significance when treating depressed patients with ECT.