Table 1.
Descriptives of confounders by cumulative cannabis use at age 16% (n)
| Cumulative cannabis use age 16 | 0 times 72.1 (1275) | <20 times 20.4 (357) | 21–60 times 4.1 (67) | >60 times 3.4 (57) | p value |
|---|---|---|---|---|---|
| Family history of depression | 25.9 (330) | 27.2 (97) | 32.8 (22) | 28.1 (16) | 0.298 |
| Family history of schizophrenia | 0.8 (10) | 1.1 (4) | 0 | 1.8 (1) | 0.625 |
| No higher maternal education | 76.8 (979) | 69.2 (247) | 62.7(42) | 68.4 (39) | 0.001 |
| Urban dwelling | 89.0 (1135) | 86.8 (310) | 89.6 (60) | 86.0 (49) | 0.353 |
| Gender (female) | 57.3 (731) | 65.3 (233) | 53.7 (36) | 43.9 (25) | 0.662 |
| Borderline personalitya | 1.5 (19) | 0.8 (3) | 0 | 0 | 0.127 |
| IQ at age 8 m(sd) | 109.2 (15.4) | 112.2 (15.2) | 117.0 (14.2) | 112.4 (13.8) | <0.001 |
| Depression at age 12b | 1.7 (22) | 4.2 (15) | 3.0 (2) | 5.3 (3) | 0.009 |
| Early onset persistent conduct disorder groupc | 5.3 (68) | 8.1 (29) | 7.5 (5) | 12.3 (7) | 0.009 |
| Peer problems (4 or more) | 7.4 (94) | 5.3 (19) | 11.9 (8) | 7.0 (4) | 0.238 |
| Bullied | 30.3 (386) | 29.7 (106) | 29.9 (20) | 28.1 (16) | 0.712 |
| Weekly or Daily cigarette smoking age 16 | 2.1 (27) | 21.0 (75) | 38.8 (26) | 70.2 (40) | <0.001 |
| Used other illicit drugs age 16 | 6.0 (76) | 31.7 (113) | 58.2 (39) | 79.0 (45) | <0.001 |
| Hazardous alcohol use age 16 | 20.9 (267) | 63.0 (225) | 61.2 (41) | 86.0 (49) | <0.001 |
a
Those with a score of 4 or over.
b
Those with a score of 17 or over.
c
As reported in Barker & Maughan (2009).