Table 1.
Sociodemographic data and plasma concentration for the tested TRP metabolites.
| Healthy Controls (n = 48) | Non-LSA (n = 33) | LSA (n = 17) | LSA vs. Non-LSA | HC vs. LSA | HC vs. Non-LSA | |
|---|---|---|---|---|---|---|
| Gender—n (%) | ||||||
| Female | 30 (62) | 19 (57) | 12 (70) | 0.3 § | 0.5 § | 0.6 § |
| Male | 18 (37) | 14 (42) | 5 (29) | |||
| Physical activity—n (%) | ||||||
| No | 19 (39) | 24 (72) | 11 (64) | 0.55 § | 0.07 § | 0.003 § |
| Yes | 29 (60) | 9 (27) | 6 (35) | |||
| Cigarette smoking—n (%) | ||||||
| No | 33 (69) | 9 (27) | 4 (23) | 0.5 § | 1.0 § | <0.001 § |
| Yes | 9 (19) | 14 (42) | 10 (59) | |||
| Ex-smoker | 6 (12) | 9 (27) | 3 (18) | |||
| BMI mean-median-SD | 23.6-23.3-3.4 | 26.4-25.0-6.2 | 24.6-25.5-4.0 | 0.4 ^ | 0.2 ^ | 0.04 ^ |
| Age at T0—years (mean-median-SD) | 52-53-8 | 51-53-8.5 | 50-49-8.8 | 0.33 ^ | 0.42 ^ | 0.31 ^ |
| TRP (μg/mL) mean-median-SD | 11.0-10.9-1.7 | 9.4-9.8-1.6 | 9.6-9.8-1.6 | 0.7 ^ | 0.0065 ^ | <0.001 ^ |
| 5-HTP (ng/mL) mean-median-SD | 69.9-60.7-34.4 | 85.7-84.2-25.4 | 91.2-92.6-35.4 | 0.7 ^ | 0.0059 ^ | 0.001 ^ |
| 5-HT (ng/mL) mean-median-SD | 260.7-241.9-167.9 | 288.7-269.9-141.2 | 363.3-380.1-204.8 | 0.29 ^ | 0.063 ^ | 0.28 ^ |
| KYN (μg/mL) mean-median-SD | 0.383-0.376-0.140 | 0.343-0.330-0.109 | 0.350-0.360-0.083 | 0.53 ^ | 0.53 ^ | 0.17 ^ |
| 3-HK (ng/mL) mean-median-SD | 44.4-42.4-13.5 | 42.8-42.2-3.2 | 41.9-41.8-1.6 | 0.36 ^ | 0.34 ^ | 0.65 ^ |
| QA (ng/mL) mean-median-SD | 158.7-154.5-45.9 | 141.2-142.6-14.5 | 145.6-141.2-15.7 | 0.6 ^ | 0.2 ^ | 0.015 ^ |
| KYNA (ng/mL) mean-median-SD | 10.2-8.3-8.0 | 8.3-8.4-4.1 | 10.2-9.9-5.5 | 0.13 ^ | 0.48 ^ | 0.67 ^ |
| 5-HTP/TRP*1000 ratio mean-median-SD | 6.4-5.7-3.2 | 9.3-9.5-3.1 | 9.5-9.2-3.3 | 0.8 ^ | <0.001 ^ | <0.001 ^ |
| KYN/TRP*1000 ratio mean-median-SD | 34.8-34.0-11.9 | 37.8-32.9-14.3 | 38.0-33.7-14.4 | 0.9 ^ | 0.47 ^ | 0.6 ^ |
| QA/KYNA ratio mean-median-SD | 22.5-20.7-14.0 | 23.1-17.4-17.8 | 24.9-13.6-25.6 | 0.17 ^ | 0.28 ^ | 0.8 ^ |
Abbreviations: HC—healthy controls; LSA—Lifetime suicide attempts; non-LSA—no Lifetime suicide attempts; TRP—tryptophan; 5-HTP— 5-hydroxytryptophan; 5-HT—serotonin; 3-HK—3-hydroxykynurenine; QA— quinolinic acid; KYNA—kynurenic acid; § χ2 p value; ^ Wilcoxon test p value.