Table 2.
Childhood Psychotic Symptoms and Risk of Mental Health Problems and Substance Use at Age 18 Years
| Young-Adult Outcomes | Model 1a | Model 2b | Model 3c | |||
|---|---|---|---|---|---|---|
| RR (95% CI) | P Value | RR (95% CI) | P Value | RR (95% CI) | P Value | |
| Mental health | ||||||
| Psychotic experiences | 1.84 (1.51, 2.23) | <.001 | 1.63 (1.34, 2.00) | <.001 | 1.44 (1.13, 1.84) | .003 |
| Psychotic symptoms | 5.34 (2.92, 9.75) | <.001 | 5.17 (2.66, 10.04) | <.001 | 4.14 (1.78, 9.59) | .001 |
| Depression | 2.02 (1.55, 2.61) | <.001 | 2.04 (1.57, 2.64) | <.001 | 1.76 (1.29, 2.40) | <.001 |
| Anxiety | 2.81 (1.84, 4.28) | <.001 | 2.96 (1.92, 4.56) | <.001 | 2.41 (1.43, 4.06) | .001 |
| Suicide attempts | 5.00 (3.07, 8.16) | <.001 | 4.84 (3.00, 7.78) | <.001 | 2.86 (1.42, 5.73) | .003 |
| Self-harm | 2.25 (1.60, 3.15) | <.001 | 2.27 (1.63, 3.15) | <.001 | 1.61 (1.09, 2.40) | .017 |
| PTSD | 1.19 (0.54, 2.65) | .661 | 1.17 (0.54, 2.53) | .694 | 1.29 (0.53, 3.11) | .577 |
| Conduct disorder | 1.65 (1.16, 2.34) | .005 | 1.33 (0.95, 1.87) | .101 | 1.19 (0.80, 1.77) | .389 |
| ADHD | 1.99 (1.25, 3.17) | .004 | 1.62 (1.02, 2.56) | .040 | 1.12 (0.62, 2.02) | .697 |
| Substance use | ||||||
| Tobacco dependence | 2.53 (1.67, 3.85) | <.001 | 2.12 (1.39, 3.25) | .001 | 2.17 (1.38, 3.39) | .001 |
| Alcohol dependence | 1.26 (0.96, 1.65) | .100 | 1.27 (0.96, 1.69) | .093 | 1.12 (0.81, 1.55) | .475 |
| Cannabis dependence | 2.11 (1.22, 3.66) | .008 | 1.66 (0.96, 2.87) | .070 | 1.60 (0.91, 2.80) | .101 |
| Dependence on other drugs | 0.89 (0.13, 5.99) | .904 | 0.76 (0.11, 5.13) | .779 | 0.96 (0.20, 4.63) | .964 |
| Cumulative score for mental health outcomes | 2.13 (1.76, 2.58) | <.001 | 1.97 (1.62, 2.38) | <.001 | 1.65 (1.31, 2.06) | <.001 |
Note: The N within each model is restricted to participants with non-missing data on all variables included in the multivariate models. The comparison group is those who did not have psychotic symptoms at age 12. Statistically significant results (P < .05) are presented in bold text. ADHD, attention-deficit hyperactivity disorder; CI, confidence interval; RR, risk ratio derived using Poisson regression; PTSD, post-traumatic stress disorder. The cumulative score for mental health outcomes was derived by summing all of the dichotomized scores for the different mental health and substance use problems.
aModel 1: adjusted for the nonindependence of twin observations.
bModel 2: further adjusted for gender, age-5 IQ, and family socioeconomic status.
cModel 3: further adjusted for psychopathology at age 12, including depression, anxiety, self-harm/suicidal behavior, ADHD, and conduct disorder.