Table 2.
Measures of Stimulant Use and ORs for FEP
| Variables | Controls (n = 1497) | FEP cases (n = 1130) | χ² P value* | Raw OR (95% CI)† | Raw OR P value | Fully adjusted OR (95% CI)† | Fully adjusted OR P value |
|---|---|---|---|---|---|---|---|
| Recent use (last year) | |||||||
| Ever used, yes n (%) | 57 (3.81) | 89 (7.88) | <.001 | 1.84 (1.29–2.62) | <.001 | 1.74 (1.20–2.54) | .004 |
| Number of weeks, mean (SD) | 4.33 (8.56) | 7.81 (12.83) | .056 | 1.05 (1.01–1.09) | .010 | 1.04 (1.00–1.08) | .034 |
| Frequency, daily/weekly/less, n | 1/11/44 | 5/20/60 | <.001 | 7.68 (0.87–67.59) 1.95 (0.92–4.16) 1.63 (1.08–2.46) |
.066 .082 .019 |
3.44 (0.39–30.60) 1.92 (0.83–4.22) 1.58 (1.02–2.45) |
.269 .105 .040 |
| Cocaine and/or stimulant use, n (%)* | 101 (6.74) | 187 (16.55) | <.001 | 2.30 (1.76–3.00) | <.001 | 2.04 (1.53–2.72) | <.001 |
| Lifetime use** | |||||||
| Ever used, yes n (%) | 162 (10.82) | 217 (14.50) | <.001 | 1.87 (1.49–2.36) | <.001 | 1.62 (1.25–2.09) | <.001 |
| Age at first use, mean (SD) | 20.77 (5.25) | 19.83 (4.58) | .825 | 1.00 (0.95–1.05) | .964 | 1.02 (0.97–1.08) | .414 |
| Age at stop, mean (SD) | 25.71 (8.5) | 24.12 (7.8) | .931 | 1.02 (0.98–1.06) | .490 | 1.04 (0.99–1.08) | .086 |
| Frequency, daily/weekly/less, n | 4/25/91 | 16/49/112 | <.001 | 6.46 (2.12–19.74) 2.73 (1.65–4.50) 1.74 (1.29–2.35) |
.001 <.001 <.001 |
3.19 (0.99–10.29) 2.29 (1.34–3.89) 1.62 (1.17–2.24) |
.052 .002 .004 |
| Cocaine and/or stimulant use, n (%) | 244 (16.30) | 358 (31.68) | <.001 | 2.18 (1.79–2.66) | <.001 | 1.82 (1.45–2.29) | <.001 |
Note: Raw ORs are adjusted only for age, sex, and ethnicity, whereas fully adjusted ORs are additionally adjusted for current cannabis use in recent stimulant use models or lifetime cannabis use in lifetime use models and education level.
FEP, first-episode psychosis; OR, odds ratio; SD, standard deviation; CI, confidence intervals.
†Reference group for both raw and fully adjusted ORs is abstainers (recent or lifetime) unless otherwise specified.
*Out of the 89 FEP patients who used stimulants last year, 62.9% also used cocaine in the past year. Out of the 217 FEP patients who have used stimulants during their lifetime, 72.8% also used cocaine during their lifetime.
**No missing data for Recent use. 26 missing data for lifetime use (13 controls, 13 FEP). None of them had used stimulants in the last year. These participants were not excluded from the analyses, and we did not observe any difference in age or sex between these 26 participants and the rest of the population (χ2P values > .05).