. Author manuscript; available in PMC: 2016 Mar 1.

Published in final edited form as: Alcohol Clin Exp Res. 2015 Jan 30;39(3):514–521. doi: 10.1111/acer.12651

Table 2.

Serum levels of tryptophan, kynurenine and the kynurenine to tryptophan ratio according to recent depression status (HSCL-25 mean cutoff >1.75 in depression subscale) and alcohol-use severity dichotomized at mean score on AUDIT scale. Values in the parentheses are standard deviation

	AUDIT score <28 (n= 65)	AUDIT score ≥28 (n= 101)	P-value^*	No depression N=118	Depression N=51	P-value^*
Tryptophan (μM)	47.6 (13.7)	46.6 (14.1)	0.639	45.7 (14.1)	49.9 (13.0)	0.047
Kynurenine (μM)	1.8 (0.6)	2.1 (0.7)	0.006	2.0 (0.7)	2.0 (0.6)	0.641
Kynurenine/tryptophan X 10³	40.4 (14.3)	48.6 (17.6)	0.002	47.5 (17.6)	41.4 (14.0)	0.028

HSCL-25: Hopkins Symptom Checklist- 25, AUDIT: Alcohol-Use Disorder Identification Test.

P-values were calculated by Student's t-test (tryptophan) and Mann Whitney U-test for the other variables. There were three missing data points for AUDIT score. Results are based on complete case analysis.