Table 1.
Sociodemographics, childhood adversities and cannabis use across all included first-episode psychosis cases and unaffected controls
| Total, n = 2112 |
Controls, n = 1231 |
Cases, n = 881 |
Controls v. cases |
|
|---|---|---|---|---|
| Age in years, M (s.d.) | 33.97 (12.58) | 36.19 (13.43) | 30.88 (10.55) | U = 8.749* |
| Sex, male, N (%) | 1124 (53.23) | 578 (46.99) | 546 (61.98) | χ2 = 46.2906* |
| Ethnicity, N (%) White Black Mixed Asian North African Other |
1447 (68.61) 277 (13.13) 215 (10.19) 64 (3.03) 65 (3.08) 41 (1.94) |
927 (75.43) 115 (9.36) 112 (9.11) 33 (2.69) 23 (1.87) 19 (1.55) |
520 (59.09) 162 (18.41) 103 (11.70) 31 (3.52) 42 (4.77) 22 (2.50) |
χ2 = 72.9084* |
| Years of education, M (s.d.) | 15.24 (10.37) | 15.32 (7.43) | 15.12 (13.43) | U = 8.462* |
| Country, N (%) UK Holland Spain France Italy Brazil |
571 (27.04) 402 (19.03) 143 (6.77) 214 (10.13) 292 (13.83) 490 (23.20) |
334 (27.13) 210 (17.06) 75 (6.09) 147 (11.94) 165 (13.40) 300 (24.37) |
237 (26.90) 192 (21.79) 68 (7.72) 67 (7.60) 127 (14.42) 190 (21.57) |
χ2 = 19.7118* |
| Childhood trauma, N (%) Household discord Psychological abuse Physical abuse Sexual abuse Bullying |
932 (44.81) 259 (12.50) 556 (26.77) 206 (9.94) 732 (36.08) |
481 (39.27) 111 (9.09) 291 (23.79) 102 (8.33) 371 (31.02) |
451 (52.75) 148 (17.39) 265 (31.03) 104 (12.26) 361 (43.34) |
χ2 = 30.8554* |
| Childhood trauma, N (%) Early trauma Late trauma |
851 (43.11) 511 (25.89) |
488 (41.22) 273 (23.06) |
363 (45.95) 238 (30.13) |
χ2 = 32.8989* |
| Lifetime cannabis use, yes N (%) | 1133 (45.07) | 568 (46.22) | 565 (64.13) | χ2 = 69.6654* |
| Age first tried cannabis, M (s.d.) | 17.51 (4.58) | 18.04 (4.60) | 16.97 (4.50) | U = 5.416* |
| Cannabis potency, N (%) Non-users Low potency (THC <10%) High potency (THC ⩾10%) |
951 (48.05) 631 (31.88) 397 (20.06) |
648 (55.86) 341 (29.40) 171 (14.74) |
303 (37.00) 290 (35.41) 226 (27.59) |
χ2 = 80.5330* |
| Cannabis frequency, N (%) Never or occasional More than once a week Daily |
604 (53.88) 190 (16.95) 327 (29.17) |
398 (70.19) 90 (15.87) 79 (13.93) |
206 (37.18) 100 (18.05) 248 (44.77) |
χ2 = 148.7712* |
Early trauma refers to exposure between birth and age 11; late trauma refers to exposure between ages 12 and 17; THC, Δ⁹-tetrahydrocannabinol; U, Mann–Whitney U test; χ2, Chi-squared test; *p value ⩽0.05.