Cerebrospinal fluid amine metabolites after combined amitriptyline-triiodothyronine treatment of depressed women.

Levels of 5-hydroxyindoleacetic acid and homovanillic acid were measured in cerebrospinal fluid from 33 depressed women with no clinical response to amitriptyline, before and after combination treatment with triiodothyronine. Although the latter showed significant clinical improvement, changes in CSF amine metabolites did not differ significantly from a control group of 16 therapy-resistant depressed women receiving higher doses of amitriptyline. Possible explanations for the mechanism of action of triiodothyronine are discussed.