| Tobacco smoking | |||
| Current smokers | 9 (36%) | 8 (35%) | >0.99 |
| Ever smokers | 19 (76%) | 14 (61%) | 0.35 |
| Alcohol use |
|
| |
| Never | 9 (36%)1 | 8 (35%) | 0.95 |
| Occasional | 9 (36%)1 | 10 (44%) | |
| Frequent | 5 (20%)1 | 5 (22%) | |
| Polydrug use† | 23 (92%) | 22 (96%) | 0.60 |
| Neuropsychological test z-scores | |||
| Learning and memory | −0.31± 1.002 | −0.28 ± 1.093 | 0.92 |
| Executive function | 0.33 ± 0.981 | −0.06 ± 1.042 | 0.20 |
| Working memory | −0.10 ± 0.721 | −0.22 ± 0.872 | 0.64 |
| Psychomotor speed | 0.27 ± 0.652 | 0.24 ± 0.592 | 0.89 |
| Global | 0.01 ± 0.594 | −0.18 ± 0.544 | 0.30 |
| Beck Depression Inventory (BDI) scores | |||
| Somatic subscore, median (Q1 - Q3) | 6.0 (3.0 - 9.0)1 | 3.0 (2.0 - 6.0) | 0.06‡ |
| Cognitive-affective subscore, median (Q1 - Q3) | 6.0 (1.0 - 9.0)1 | 5.0 (2.0 - 9.0) | 0.48‡ |
| Total score, median (Q1 - Q3) | 12.0 (6.0 - 17.0)1 | 9.0 (5.0 - 15.0) | 0.21‡ |