Table 3. Effects of risk factors on odds of observing psychotic features in visits during the first year after entering the study.
| Unadjusted | Adjusted* (n = 409, 3,625 Observations) | ||||
|---|---|---|---|---|---|
| n, Observations | OR (95% CI) | p-Value | OR (95% CI) | p-Value | |
| Covariates | |||||
| Time (months) | 428, 4,294 | 0.94 (0.91–0.97) | <0.001 | 0.96 (0.93–1.00) | 0.07 |
| Age | 428, 4,294 | 0.96 (0.94–0.99) | 0.002 | 1.00 (0.98–1.03) | 0.78 |
| Male | 428, 4,294 | 1.79 (0.94–3.39) | 0.07 | 1.82 (1.03–3.21) | 0.04 |
| Time-invariant risk factors | |||||
| Past psychotic disorder diagnosis | 428, 4,294 | 14.05 (8.96–22.03) | <0.001 | 17.77 (10.83–29.15) | <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 of psychosis assessment | |||||
| Daily tobacco use | 428, 4,193 | 1.49 (0.96–2.31) | 0.07 | – | – |
| Days using alcohol | 427, 4,262 | 1.11 (1.03–1.20) | 0.007 | 1.09 (1.01–1.18) | 0.04 |
| Days using methamphetamine | 426, 4,233 | 1.13 (1.05–1.22) | 0.002 | 1.14 (1.05–1.24) | 0.001 |
| Days using cannabis | 426, 4,235 | 1.08 (1.03–1.13) | 0.002 | 1.08 (1.02–1.14) | 0.008 |
| Days using cocaine | 426, 4,235 | 1.07 (1.01–1.13) | 0.009 | – | – |
| Days using opioid | 426, 4,234 | 1.05 (0.99–1.12) | 0.08 | – | – |
| Concurrent month of psychosis assessment | |||||
| rTHQ score | 410, 3,775 | 1.50 (1.16–1.93) | 0.002 | 1.54 (1.19–2.00) | 0.001 |
| 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 | 2.04 (1.26–3.30) | 0.004 |
| Adequate methadone therapy | 427, 4,147 | 0.90 (0.62–1.30) | 0.58 | – | – |
Data are OR and 95% CI. Abbreviations: AIC, Akaike Information Criterion; CI, confidence interval; OR, odds ratio; rTHQ, recent THQ; TBI, traumatic brain injury; THQ, Trauma History Questionnaire.
*Adjusted model selected for optimal fit by AIC and likelihood ratio test. Fixed effects are adjusted for the included time-invariant, time-varying factors, and covariates. Random effects (standard deviation): subject (1.94), 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 number of days of substance use in the week concurrent with the psychosis assessment visit and 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).