Table 4. Effects of urine drug screen results rather than self-report of substance use on odds of observing psychotic features in visits during the first year after entering the study.
| Unadjusted | Adjusted* (n = 389, 2,816 Observations) | ||||
|---|---|---|---|---|---|
| n, Observations | OR (95% CI) | p-Value | OR (95% CI) | p-Value | |
| Covariates | |||||
| Time (months) | 428, 4,294 | 0.94 (0.91–0.98) | <0.001 | 0.96 (0.92–1.00) | 0.06 |
| Age | 428, 4,294 | 0.96 (0.94–0.99) | 0.002 | 1.02 (0.99–1.04) | 0.20 |
| Male | 428, 4,294 | 1.79 (0.94–3.39) | 0.07 | 1.85 (1.05–3.27) | 0.03 |
| Time-invariant risk factors | |||||
| Past psychotic disorder diagnosis | 428, 4,294 | 14.05 (8.96–22.03) | <0.001 | 15.04 (9.18–24.64) | <0.001 |
| THQ score by age 18† | 420, 4,207 | 1.18 (1.07–1.31) | 0.001 | – | – |
| Persistent sequelae of TBI | 428, 4,294 | 1.36 (0.56–3.29) | 0.49 | – | – |
| Homelessness by age 18 | 424, 4,256 | 1.16 (0.65–2.07) | 0.62 | – | – |
| Time-varying risk factors over the first year after entering the study | |||||
| Concurrent week urine drug screen | |||||
| Methamphetamine | 415, 3,276 | 2.05 (1.48–2.83) | <0.001 | 2.44 (1.72–3.44) | <0.001 |
| Cannabis | 415, 3,274 | 1.79 (1.33–2.42) | <0.001 | 1.47 (1.06–2.02) | 0.02 |
| Cocaine | 415, 3,277 | 0.88 (0.64–1.21) | 0.43 | – | – |
| Opioid | 415, 3,273 | 1.27 (0.95–1.71) | 0.11 | – | – |
| Concurrent month | |||||
| rTHQ score‡ | 410, 3,775 | 1.50 (1.16–1.93) | 0.002 | 1.52 (1.14–2.03) | 0.004 |
| Homelessness | 428, 4,230 | 1.35 (0.65–2.80) | 0.41 | – | – |
| Adequate antipsychotic treatment | 427, 4,158 | 2.78 (1.76–4.40) | <0.001 | 1.91 (1.13–3.23) | 0.02 |
| Adequate methadone therapy | 427, 4,147 | 0.90 (0.63–1.30) | 0.58 | – | – |
Data are OR and 95% CI. Abbreviations: CI, confidence interval; OR, odds ratio; rTHQ, recent THQ; TBI, traumatic brain injury; THQ, Trauma History Questionnaire.
*Adjusted for all time-invariant, time-varying factors, and covariates included. Random effects (standard deviation): subject (1.71), time point (0.22).
†Linear effects of THQ scores for number of traumatic events by age 18. Quadratic effects were not significant (p > 0.10).
‡Linear effects of rTHQ scores for the number of traumatic events (0, 1, or ≥2) in the month concurrent with the assessment visit are reported. Quadratic effects were not significant (p > 0.10).