Table 2.
Demographic characteristics and ketamine-using history of the RDS-sample in Taipei Metropolitan Area (N = 1115), by illicit drug use experience
| Variables | Illicit drug-naïve (Group 1; N = 840) |
Exclusive ketamine use (Group 2; N = 30) |
Polydrug ketamine use (Group 3; N = 132) |
The other illicit drug use (Group 4; N = 113) |
Group comparisons | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| N | %wt | 95% CI | N | %wt | 95% CI | N | %wt | 95% CI | N | %wt | 95% CI | Pc | Post-hocd | |
| Male | 504 | 55.4 | (49.3–62.0) | 10 | 63.2 | (37.6–86.4) | 44 | 59.7 | (45.9–73.8) | 36 | 64.5 | (50.2–79.6) | .160 | – |
| Education < college | 513 | 65.9 | (60.0–71.5) | 23 | 83.0 | (63.2–96.8) | 94 | 71.3 | (57.6–82.5) | 71 | 69.6 | (55.6–81.6) | .141 | – |
| Unemployment | 39 | 5.8 | (3.4–8.4) | 3 | 10.8 | (0.0–29.0) | 16 | 14.5 | (3.7–28.5) | 21 | 22.6 | (7.8–39.6) | < .001 | 3, 4 > 1 |
| Early-onseta tobacco use | 265 | 26.7 | (22.0–30.9) | 17 | 61.8 | (38.2–85.9) | 72 | 47.5 | (35.7–62.1) | 52 | 52.5 | (37.1–63.8) | <.001 | 2, 3, 4 > 1 |
| Early-onseta alcohol useb | 290 | 29.8 | (25.4–34.9) | 15 | 47.9 | (23.7–74.4) | 64 | 45.8 | (33.5–58.8) | 58 | 57.6 | (43.4–70.0) | <.001 | 3, 4 > 1 |
| N | Mean | SD | N | Mean | SD | N | Mean | SD | N | Mean | SD | Pc | Post-hocd | |
| Age in years | 840 | 28.1 | 8.2 | 30 | 21.8 | 3.6 | 132 | 26.0 | 5.5 | 113 | 30.1 | 7.6 | < .001 | 1 > 2, 3; 4 > 3 > 2 |
| Age at first tobacco use | 772 | 17.1 | 3.7 | 29 | 14.6 | 2.1 | 129 | 15.4 | 3.3 | 110 | 15.6 | 3.0 | < .001 | 1 > 2, 3, 4 |
| Age at first alcohol use | 766 | 16.0 | 4.1 | 29 | 14.9 | 3.1 | 130 | 14.6 | 3.5 | 109 | 15.2 | 3.9 | < .001 | 1 > 3 |
aAn onset use age of < 16 years, which is the end of compulsory education up to middle school, is defined as early–onset use
bThree individuals were missing on the information on onset age of alcohol use
cχ2 test or Fisher’s exact test for categorical variables; ANOVA for quantitative variables
dTukey’s HSD test in ANOVA; a Tukey-type multiple comparison for proportions in a 2*4 cross-tabulation for categorical variables (Elliott and Reisch 2006)