Table 1.
Clinical and biochemical data
| ADHD | N | Control | N | p value | |
|---|---|---|---|---|---|
| 133 | 131 | ||||
| Female, N (%) | 71 (53.4) | 133 | 75 (57.3) | 131 | 0.52a |
| Age (range 18–40), median (SD) | 28.0 (6.5) | 133 | 22.5 (2.8) | 131 | <0.001***b |
| Alcohol problems, N (%) | 24 (19.2) | 125 | 1 (0.8) | 131 | <0.001***a |
| Problems with illicit drugs, N (%) | 34 (27.0) | 126 | 0 (0.0) | 131 | <0.001***a |
| Serious anxiety and/or depression, N (%) | 82 (65.1) | 126 | 5 (3.8) | 126 | <0.001***a |
| Bipolar disorder, N (%) | 12 (9.9) | 121 | 0 (0.0) | 131 | <0.001***a |
| Moderate smokersd, N (%) | 51 (38.3) | 133 | 12 (9.2) | 131 | <0.001***a |
| Heavy smokersd, N (%) | 27 (27.8) | 133 | 4 (3.1) | 131 | <0.001***a |
| Total WURS (range 0–100), median (SD) | 60.0 (16.9) | 118 | 12.0 (10.4) | 129 | <0.001***b |
| Total ASRS (range 0–72), median (SD) | 47.0 (11.6) | 123 | 22.0 (7.7) | 128 | <0.001***b |
| Combined typee, N (%) | 65 (52.8) | 123 | 3 (2.3) | 128 | <0.001***a |
| Hyperactive typee, N (%) | 3 (2.4) | 123 | 1 (0.8) | 128 | 0.32a |
| Inattentive typee, N (%) | 31 (25.2) | 123 | 4 (3.1) | 128 | <0.001***a |
| Tryptophanf, i | 77.3 (68.1–92.3) | 133 | 83.6 (76.6–94.0) | 130 | 0.004**c |
| Kynureninef, i | 1.51 (1.29–1.78) | 133 | 1.57 (1.40–1.76) | 130 | 0.15c |
| Kynurenine/tryptophan ratio (KTR)g, i | 19.0 (16.5–21.6) | 133 | 18.4 (16.7–20.8) | 130 | 0.46c |
| 3-hydroxykynurenine (HK)h, i | 31.8 (22.2–39.4) | 131 | 30.6 (26.1–28.1) | 130 | 0.43c |
| Kynurenic acid (KA)h, i | 38.9 (30.9–52.2) | 131 | 46.7 (34.0–57.5) | 130 | 0.03*c |
| Xanthurenic acid (XA)h, i | 14.2 (11.0–22.4) | 131 | 18.9 (13.7–24.7) | 130 | 0.004**c |
| Anthranilic acid (AA)h, i | 19.4 (13.2–24.3) | 131 | 17.6 (14.9–22.8) | 130 | 0.52c |
| 3-hydroxyanthranilic acid (HAA)h, i | 29.8 (20.0–40.1) | 131 | 35.4 (29.2–46.5) | 130 | <0.001***c |
| Quinolinic acid (QA)h, i | 303 (258–387) | 131 | 306 (274–364) | 130 | 0.76c |
| Riboflavin (Vit. B2)h, i | 18.1 (12.7–25.9) | 131 | 19.9 (16.1–28.3) | 130 | 0.02*c |
| Total vitamin B6h, i | 58.5 (41.8–83.9) | 131 | 67.1 (49.0–88.4) | 130 | 0.05*c |
| Cotinineh, i | 678 (2.48–1088) | 131 | 1.2 (0.55–6.06) | 130 | <0.001***c |
Significance <0.001: ‘***’, <0.01: ‘**’, <0.05: ‘*’
aχ2 test
bStudent’s T test
cMann–Whitney U test
dCalculated based on serum cotinine levels: 80–1000 nmol/l: moderate smoker, >1000 nmol/l: heavy smoker
eCalculated based on ASRS scores: A score of 21 or higher on the nine questions on inattentiveness is indicative of inattentive type, while a score of 21 or higher on the hyperactivity/impulsive questions is indicative for hyperactive/impulsive type. Combined type requires a score of 21 or higher on both subscales
fμmol/L
gμmol/μmol
h nmol/L
iMedian (25–75 percentile)