Table 4.
Substance Abuse (None v. Any) among 1049 SHIP participants with schizophrenia or schizoaffective disorder who reported using any antipsychotic medication in the past 4 weeks, by use of clozapine
| Clozapine | ||||||
|---|---|---|---|---|---|---|
| No | Yes | |||||
| n | % | n | % | Adjusted odds ratio† | 95% CI | |
| Alcohol | ||||||
| Lifetime | 727 | 91.9 | 240 | 93.4 | 1.184 | 0.674–2.080 |
| Past year | 598 | 82.4 | 168 | 70.3 | 0.516*** | 0.366–0.727 |
| Cannabis | ||||||
| Lifetime | 544 | 69.2 | 180 | 70.6 | 1.046 | 0.764–1.433 |
| Past year | 298 | 37.8 | 50 | 19.7 | 0.398*** | 0.282–0.563 |
| ‘Other’ substances | ||||||
| Lifetime | 375 | 47.8 | 92 | 36.1 | 1.014 | 0.757–1.360 |
| Past year | 132 | 16.9 | 18 | 7.1 | 0.452* | 0.245–0.835 |
| Amphetamine | ||||||
| Lifetime | 311 | 39.7 | 103 | 40.2 | 0.653** | 0.486–0.878 |
| Past year | 80 | 10.2 | 13 | 5.1 | 0.368*** | 0.219–0.620 |
| Nicotine dependence§ | ||||||
| Very low | 268 | 33.8 | 102 | 39.7 | 0.811 | 0.4901.341 |
| Low | 80 | 10.1 | 27 | 10.5 | 0.909 | 0.542–1.522 |
| Moderate | 76 | 9.6 | 25 | 9.7 | 0.715 | 0.488–1.047 |
| High | 197 | 24.9 | 56 | 21.8 | 0.692 | 0.462–1.036 |
| Very high | 171 | 21.6 | 47 | 18.3 | 1.0 | |
SHIP, survey of high impact psychosis; OR, odds ratio; CI, confidence interval.
Missing cases: alcohol lifetime = 1, past year = 84; cannabis lifetime = 9, past year = 7; amphetamines lifetime = 9, past year = 11; other substances lifetime = 10, past year = 9.
†
All variables are adjusted for chronicity and diagnosis.
§
As rated on the Fagerstrom test for nicotine dependence.
*p < 0.05, **p < 0.01, and ***p < 0.001.