Table 3.
Predictors of Time to Onset of Psychosis, Assessed Using Time-dependent Use Quantities during Key Periods of Illness Course and Development (Multi-state Models)
| Predictor | HR | Z | p | |
|---|---|---|---|---|
| Model 1: All premorbid marijuana use | ||||
| Marijuana dosage (joints) | 1.12 | 4.37 | <0.0005 | |
| Model 2: All premorbid use of marijuana, alcohol, and tobacco | ||||
| Marijuana dosage (joints) | 1.14 | 4.15 | <0.0005 | |
| Alcohol dosage (drinks) | 0.97 | −0.98 | 0.33 | |
| Tobacco dosage (cigarettes) | 1.00 | 0.02 | 0.99 | |
| Model 3: Premorbid use, pre-prodrome and post-prodrome (but pre-psychosis) use | ||||
| Pre-prodrome | Marijuana dosage (joints) | 1.11 | 1.88 | 0.06 |
| Alcohol dosage (drinks) | 0.87 | −2.24 | 0.03 | |
| Tobacco dosage (cigarettes) | 0.92 | −2.06 | 0.04 | |
| Post-prodrome | Marijuana dosage (joints) | 1.11 | 2.56 | 0.01 |
| Alcohol dosage (drinks) | 1.04 | 0.97 | 0.33 | |
| Tobacco dosage (cigarettes) | 1.04 | 1.37 | 0.17 | |
| Model 4: Premorbid use during developmental periods | ||||
| Early adolescence (12–14) | Marijuana dosage (joints) | 1.08 | 0.31 | 0.76 |
| Alcohol dosage (drinks) | 1.38 | 1.29 | 0.20 | |
| Tobacco dosage (cigarettes) | 0.92 | −0.37 | 0.71 | |
| Late adolescence (15–17) | Marijuana dosage (joints) | 1.22 | 1.60 | 0.11 |
| Alcohol dosage (drinks) | 1.08 | 0.51 | 0.61 | |
| Tobacco dosage (cigarettes) | 0.88 | −1.26 | 0.21 | |
| Adulthood (>17) | Marijuana dosage (joints) | 1.13 | 3.87 | <0.0005 |
| Alcohol dosage (drinks) | 0.96 | −1.21 | 0.23 | |
| Tobacco use (cigarettes) | 1.01 | 0.27 | 0.79 | |