. Author manuscript; available in PMC: 2013 Jul 15.

Published in final edited form as: J Child Psychol Psychiatry. 2010 Apr 12;51(8):935–943. doi: 10.1111/j.1469-7610.2010.02245.x

Table 2.

Mean (SD) plasma concentrations (in ng/ml) of kynurenine (KYN), tryptophan (TRP), 3-hydroxyanthranilic acid (3-HAA), KYN/TRP [estimate of indoleamine 2,3-dioxygenase (IDO) activity], and 3-HAA/KYN [estimate of neurotoxic load] in adolescents with melancholic major depressive disorder (MDD), non-melancholic MDD, and healthy controls.

Measure	Melancholic MDD n = 20	Non-melancholic MDD n = 30	Healthy controls n = 22
KYN	375.60 (146.70)	373.26 (133)	408.65 (148.08)
TRP	718.59^a,^c (727.12)	1022.77 (643.03)	982.87 (406.31)
3-HAA	9009.68 (2060.33)	9235.25 (2695.44)	9630.58 (2251.77)
KYN/TRP	.76^b,^d (.41)	.45 (.21)	.49 (.27)
3-HAA/KYN	25.76 (6.69)	25.96 (5.99)	24.77 (4.43)

Compared to healthy controls (p = .022).

Compared to healthy controls (p = .008).

Compared to non-melancholic MDD (p = .006).

Compared to non-melancholic MDD (p = .001).