Table 1.
Descriptive statistics
| Study variables | Numbers (percentages) | ||
|---|---|---|---|
| Sex | Male | 353 (49.7%) | |
| Intervention group | Intervention | 347 (48,9%) | |
| Control | 363 (51,1%) Age 17 | Age 22 | |
| Cannabis use | Never | 486 (81.8%) | 477 (72,9%) |
| Once or twice | 51 (8,6%) | 47 (7,2%) | |
| Once a month | 6 (1.0%) | 14 (2,1%) | |
| Once every 2–3 weeks | 13 (2,2%) | 17 (2,6%) | |
| Once a week | 5 (0,8%) | 11 (1,7%) | |
| 2–3 times a week | 17 (2,9%) | 24 (3,7%) | |
| Once a day | 8 (1,3%) | 27 (4,1%) | |
| 2–3 times/day or more | 8 (1,3%) | 37 (5,7%) | |
| Tobacco use | Never | 497 (83,5%) | 402 (61,5%) |
| Once or twice | 21 (3,5%) | 47 (7,2%) | |
| Once a month | 1 (0,2%) | 7 (1,1%) | |
| Once every 2–3 weeks | 10 (1,7%) | 19 (2,9%) | |
| Once a week | 6 (1,0%) | 15 (2,3%) | |
| 2–3 times a week | 9 (1,5%) | 22 (3,4%) | |
| Once a day | 5 (0,8%) | 15 (2,3%) | |
| 2–3 times/day or more | 46 (7,7%) | 127 (19,4%) | |
| Alcohol use | Never | 394 (66,7%) | 115 (17,9%)_ |
| Once or twice | 113 (19,1%) | 99 (15,4%) | |
| Once a month | 20 (3,4%) | 49 (7,6%) | |
| Once every 2–3 weeks | 34 (5,8%) | 98 (15,2%) | |
| Once a week | 16 2,7%) | 112 (17,4%) | |
| 2–3 times a week | 14 (2,4%) | 148 (23,0%) | |
| Once a day | 0 (0,0%) | 15 (2,3%) | |
| 2–3 times/day or more | 0 (0,0%) | 7 (1,1%) | |
| Perception of friends’ use of illicit drugs | No | 694 (97,6%) | 674 (94,8) |
| Yes | 17 (2,4%) | 37 (5,2) | |
Note. Due to missings the numbers do not sum up to 711.