Table 1.
Demographic characteristics of the study population across diagnostic groups.
| Characteristic | Healthy volunteers n=31 | Total Depressed n=30 | χ 2 | df | p | Suicide Attempters n=14 | Suicide Non-Attempters n=16 | χ 2 | df | p |
|---|---|---|---|---|---|---|---|---|---|---|
| Sex (% male) | 32.3% | 53.3% | 2.769 | 1 | 0.096 | 64.3% | 43.8% | 1.265 | 1 | 0.261 |
| Race (% white) | 48.4% | 63.3% | 1.380 | 1 | 0.240 | 57.1% | 68.8% | 0.433 | 1 | 0.510 |
| Smoker (% yes) | 6.5% | 23.3% | 3.455 | 1 | 0.063 | 35.7% | 12.5% | 2.249 | 1 | 0.134 |
| Mean values | t-score | df | p | t-score | df | p | ||||
|
| ||||||||||
| Age (yrs) | 35.68(13.92) | 37.80 (13.08) | 0.613 | 59 | 0.613 | 34.07 (13.52) | 41.06 (12.20) | −1.489 | 28 | 0.148 |
| BMI (kg*m−2) | 24.25 (5.7) | 25.30 (5.46) | 0.724 | 57 | 0.472 | 26.23 (6.76) | 24.43 (3.90) | 0.887 | 27 | 0.383 |
| Education (yrs) | 16.10 (3.22) | 14.79 (2.54) | −1.734 | 58 | 0.088 | 13.69 (2.17) | 15.69 (2.52) | −2.251 | 27 | 0.033* |
| HDRS-17 | N/A | 20.13 (3.40) | N/A | N/A | N/A | 19.14 (3.11) | 21.00 (3.50) | −1.526 | 28 | 0.138 |
| BDI | N/A | 25.87 (8.22) | N/A | N/A | N/A | 25.5 (9.04) | 26.19 (7.70) | −0.225 | 28 | 0.824 |
| KYNb (μmol/L) | 1.33 (0.36) | 1.50 (0.34) | 1.853 | 59 | 0.069 | 1.64 (0.33) | 1.37 (0.30) | 2.263 | 28 | 0.032* |
| TRP (μmol/L) | 60.21 (7.7) | 59.15(10.4) | −0.455 | 59 | 0.651 | 63.18 (10.6) | 55.61 (9.15) | 2.099 | 28 | 0.045* |
| KYN:TRP ratio | 22.18 (5.5) | 25.62 (5.7) | 2.385 | 59 | 0.020* | 26.60 (7.14) | 24.76 (4.22) | 0.873 | 28 | 0.390 |
Abbreviations: BDI, Beck Depression Inventory, BMI, body-mass index; HDRS-17, Hamilton Depression Rating Scale (17-item); KYN, kynurenine; MDD, Major Depressive Disorder; SD, standard deviation; TRP, tryptophan.
a
Test performed was a one-way Analysis of Variance with contrasts.
*
p < 0.05.