Table 1 Demographic and clinical characteristics of the CHR and healthy control groups
|  | CHR n = 162 | HC n = 105 |  |  |
|---|---|---|---|---|
|  | n (%) | n (%) | χ 2 | p-value |
Sex | Â | Â | Â | Â |
 Male | 96 (59) | 57 (54) | 0.62 | 0.43 |
 Female | 66 (41) | 48 (46) | ||
Race | Â | Â | Â | Â |
 First Nations | 2 (1) | 2 (2) | 10.1 | 0.26 |
 Asian | 9 (6) | 10 (10) | ||
 Black | 35 (22) | 28 (27) | ||
 Latin America/Middle East/White | 93 (57) | 59 (55) | ||
 Inter-racial | 23 (14) | 6 (6) | ||
AUS/DUS cannabis use frequency | Â | Â | Â | Â |
Abstinent | 112 (69) | 92 (88) | 17.1 | 0.004 |
 1–4 times per month | 26 (16) | 11 (10) | ||
 1–4 times per week | 21 (13) | 2 (2) | ||
 Almost daily | 3 (2) | 0 (0) | ||
AUS/DUS cannabis use severity | Â | Â | Â | Â |
 Abstinent | 116 (72) | 92 (88) | 11.7 | 0.003 |
 Use without impairment | 37 (23) | 13 (12) | ||
 Abuse | 9 (6) | 0 (0) | ||
| Â | Mean (SD) | Mean (SD) | t | p-value |
Age (years) | 19.4 (4.21) | 19.5 (4.62) | 0.25 | 0.80 |
Education (years) | 11.8 (2.50) | 12.7 (3.46) | 2.32 | 0.02 |
Age at onset of cannabis use (years)a | 16.1 (3.20) | 16.0 (2.30) | 0.25 | 0.81 |