Studies of Alpha-methyl-para-tyrosine, L-dopa, and L-tryptophan in Depression and Mania

L-dopa and L-tryptophan, metabolic precursors of norepinephrine and serotonin respectively, and αMPT, a blocker of catecholamine synthesis, were administered to depressed and manic patients in an attempt to decrease their psychopathology and to test the monoamine theory of affective disorders. L-dopa and αMPT clearly altered mood and thought patterns in some patients, while L-tryptophan was less active. Analysis of urinary and cerebrospinal fluid amine metabolites documented the metabolic effects of the compounds during periods of behavioral change.