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*P<0.05 considered statistically significant
| Substance type | Before prohibition, mean, g/ml/day | After prohibition, mean, g/ml/day | P-value* |
| Tobacco | 15 | 12 | 0.041 |
| Opioids | 20 | 25 | 0.012 |
| Cannabis | 10 | 12 | 0.035 |
| Inhalants | 5 | 4 | 0.056 |
