Table 1. Characteristics of study populations with and without ADHD symptoms.
| % (N) | ADHD | χ2 | ||
|---|---|---|---|---|
| Symptomatic,% (N) | Non-symptomatic, % (N) | |||
| Gender | ||||
| Male | 52.4 (980) | 8.8 (86) | 91.2 (895) | 3.028 |
| Female | 47.6 (892) | 6.6 (59) | 93.4 (832) | |
| Grade | ||||
| One | 57.7(1079) | 6.3 (68) | 93.7 (1013) | |
| Two | 25.6 (480) | 8.1 (39) | 91.9 (440) | 15.7608** |
| Three | 12.4 (233) | 10.5 (25) | 89.5 (213) | |
| Four | 4.3 (80) | 17.6 (13) | 82.4 (61) | |
| Smoking (ever) | ||||
| Yes | 38.6 (690) | 53.6 (74) | 37.3 (616) | 14.3031*** |
| Smoked last 30 days | ||||
| Yes | 18.7 (346) | 29.6 (42) | 17.8 (304) | 11.9094*** |
| Smoking (more than one cigarette per day) | ||||
| Yes | 8.6 (161) | 14.5 (21) | 8.1 (140) | 6.9186** |
| Drinking (ever) | ||||
| Yes | 78.4 (1444) | 91.4 (127) | 77.4 (1317) | 14.8642*** |
| Drank last 30 days (at least one drink one cup per day) | ||||
| Yes | 56.5 (985) | 55.3 (78) | 42.4 (679) | 8.7873** |
| Intoxicated at least once over the past year | ||||
| Yes | 31. 6 (545) | 52.8 (75) | 29.6 (470) | 43.3637*** |
| Anxiety | ||||
| Yes | 17.6 (329) | 64.1 (93) | 13.7 (236) | 235.2426*** |
| Depression | ||||
| Yes | 19.4(363) | 66.9 (97) | 15.4 (266) | 226.9267*** |
| Total | 100.0 (1872) | 7.6 (145) | 92.3(1727) | — |
**p < 0.001, ***p < 0.0001.