Table 3.
Baseline characteristics of participants.
| Characteristics | Intervention 1 (Chat and self-help) (n = 114) |
Intervention 2 (Self-help only) (n = 108) |
Control group (Waiting list) (n = 89) | Total (n = 311) |
test value | P |
|---|---|---|---|---|---|---|
| Sex, n (%) | X22 = 7.740 | 0.02 | ||||
| Female | 30 (26.3) | 21 (19.4) | 33 (37.1) | 84 (27) | ||
| Male | 84 (73.7) | 87 (80.6) | 56 (62.9) | 227 (73) | ||
| Age in years, M (SD) | 33.5 (8.1) | 33.3 (7.4) | 32.3 (7.2) | 33.1 (7.6) | F2 = 0.679 | 0.51 |
| Age range, n (%) | X28 = 4.962 (n = 310) | 0.76 | ||||
| ≤20 years | 7 (6.2) | 4 (3.7) | 6 (6.7) | 17 (5.5) | ||
| 21–25 years | 10 (8.8) | 11 (10.2) | 8 (9) | 29 (9.3) | ||
| 26–30 years | 24 (21.2) | 20 (18.5) | 23 (25.8) | 73 (21.7) | ||
| 31–35 years | 28 (24.8) | 32 (29.6) | 27 (30.3) | 95 (28.2) | ||
| 36+ years | 44 (38.9) | 41 (38) | 25 (28.1) | 117 (34.7) | ||
| Highest education, n (%) | X28 = 9.276 | 0.32 | ||||
| Primary school | 6 (5.5) | 7 (6.6) | 9 (10.2) | 22 (7.3) | ||
| Apprenticeship | 43 (39.4) | 53 (50) | 30 (34.1) | 126 (41.6) | ||
| Secondary school | 13 (11.9) | 10 (9.4) | 16 (18.2) | 39 (12.9) | ||
| Technical college | 27 (24.8) | 23 (21.7) | 19 (21.6) | 69 (22.8) | ||
| University | 20 (18.3) | 13 (12.3) | 14 (15.9) | 47 (15.5) | ||
| Origin, n (%) | ||||||
| Canton of Zurich | 48 (42.1) | 30 (27.8) | 36 (40.4) | 114 (36.7) | X26 = 10.421 | 0.11 |
| Other Cantons | 46 (40.4) | 60 (55.6) | 44 (49.4) | 150 (48.2) | ||
| Germany | 17 (14.9) | 17 (15.7) | 9 (10.1) | 43 (13.8) | ||
| Other countries | 3 (2.6) | 1 (0.9) | 0 (0) | 4 (1.3) | ||
| SDSa, M (SD) | 8.3 (2.6) | 8.2 (2.7) | 8.7 (2.7) | 8.4 (2.7) | F2 = 0.918 | 0.40 |
| Weekly quantity of cocaine use, in grams, M (SD) | 3.5 (3.4) | 4.0 (3.6) | 4.1 (3.7) | 3.8 (3.5) | F2 = 0.890 | 0.41 |
| Days of cocaine use over past 30 days, n (%) | 11.7 (7.9) | 11.9 (7.8) | 13.3 (8.2) | 12.2 (7.9) | F2 = 1.085 | 0.34 |
| Number of years of cocaine use, M (SD) | 6.6 (5.4) | 7.1 (6.3) | 6.9 (6.3) | 6.9 (5.9) | F2 = 0.170 (n = 300) | 0.84 |
| Days of other substance use over past 30 days, M (SD) | ||||||
| Risky alcohol useb | 8.2 (8.8) | 6.6 (7.9) | 6.6 (8.2) | 7.2 (8.3) | F2 = 0.903 (n = 215) | 0.41 |
| Cannabinoids | 6.1 (9.9) | 6.3 (10.5) | 7.9 (11.3) | 6.6 (10.5) | F2 = 0.572 (n = 207) | 0.57 |
| Amphetamines | 0.9 (2.3) | 2.1 (4.9) | 2.6 (6.9) | 1.9 (4.9) | F2 = 2.003 (n = 206) | 0.14 |
| Relaxants | 2.7 (7.4) | 2.5 (8.5) | 0.9 (4.6) | 2.2 (7.2) | F2 = 0.967 (n = 179) | 0.38 |
| Hallucinogens | 0.1 (0.2) | 0.2 (0.5) | 0.2 (0.9) | 0.1 (0.6) | F2 = 0.938 (n = 176) | 0.39 |
| Heroin | 0.5 (3.8) | 0.0 (0.1) | 0 (0) | 0.2 (2.3) | F2 = 1.016 (n = 176) | 0.36 |
| Methadone | 0 (0) | 0.5 (3.7) | 0.6 (4.3) | 0.4 (3.2) | F2 = 0.578 (n = 174) | 0.56 |
| MHI-5c, M (SD) | 49.4 (18.7) | 50.5 (17.1) | 49.4 (18.8) | 49.8 (18.1) | F2 = 0.130 | 0.88 |
| ADHDd, n (%) | 40 (25.4) | 32 (31.1) | 34 (40.5) | 106 (35.3) | X22 = 1.793 | 0.41 |
aSeverity of Dependence Scale (SDS) scores range from 0 to 15, with a screening cut-off of ≥3 for cocaine dependence. b Risky alcohol use was defined as five or more standard drinks per day. A standard drink was defined as 5 cl spirits, 15–20 cl wine, or 22–45 cl beer. cMental Health Inventory (MHI-5): higher values represent improved symptoms. MHI-5 values range from 0 to 100 with a cut-off of <70 for clinically-relevant symptoms. d ADHD according to the World Health Organization Adult ADHD Self-Report Scale (ASRS) designed for ADHD screening in the general population.