Table 3.
Baseline characteristics of participants.
| Characteristics | Study arm 1a (n=114) | Study arm 2b (n=101) | Study arm 3c (n=93) | Total (n=308) | χ2, ANOVAd, or Kruskal-Wallis test | P | |
| Sex, n (%) |
|
|
|
|
χ2 2=4.3 (n=308) | .12 | |
|
|
Female | 35 (30.7) | 24 (23.8) | 17 (18) | 76 (24.7) |
|
|
|
|
Male | 79 (69.3) | 77 (76.2) | 76 (82) | 232 (75.3) |
|
|
| Age in years, mean (SD) | 28.4 (9.6) | 30.2 (9.2) | 31.0 (11.1) | 29.8 (10.0) | F 2,308=1.940 | .15 | |
| Age range, n (%) |
|
|
|
|
χ2 2=3.9 (n=308) | .14 | |
|
|
≤20 years | 24 (21.1) | 12 (11.9) | 18 (19) | 54 (17.5) |
|
|
|
|
21-25 years | 31 (27.2) | 19 (18.8) | 13 (14) | 63 (20.5) |
|
|
|
|
26-30 years | 16 (14.0) | 29 (28.7) | 19 (20) | 64 (20.8) |
|
|
|
|
31-35 years | 17 (14.9) | 18 (17.8) | 15 (16) | 50 (16.2) |
|
|
|
|
36-40 years | 14 (12.3) | 10 (9.9) | 11 (12) | 35 (11.4) |
|
|
|
|
41-45 years | 6 (5.3) | 5 (5.0) | 7 (8) | 18 (5.8) |
|
|
|
|
46+ years | 6 (5.3) | 8 (7.9) | 10 (11) | 24 (7.8) |
|
|
| Highest education, n (%) |
|
|
|
|
χ2 10=8.6 (n=308) | .57 | |
|
|
Not specified | 4 (3.5) | 3 (3.0) | 5 (5) | 12 (3.9) |
|
|
|
|
Primary school | 18 (15.8) | 12 (11.9) | 11 (12) | 41 (13.3) |
|
|
|
|
Apprenticeship | 43 (37.7) | 38 (37.6) | 41 (44) | 122 (39.6) |
|
|
|
|
Secondary school | 19 (16.7) | 13 (12.9) | 17 (18) | 49 (15.9) |
|
|
|
|
Technical college | 18 (15.8) | 26 (25.7) | 13 (14) | 57 (18.5) |
|
|
|
|
University | 12 (10.5) | 9 (8.9) | 6 (7) | 27 (8.8) |
|
|
| Origin, n (%) |
|
|
|
|
χ2 6=8.1 (n=308) | .23 | |
|
|
Canton of Zurich | 52 (45.6) | 33 (32.7) | 42 (45) | 127 (41.2) |
|
|
|
|
Other cantons | 53 (46.5) | 61 (60.4) | 48 (52) | 162 (52.6) |
|
|
|
|
Germany | 8 (7.0) | 5 (5.0) | 3 (3) | 16 (5.2) |
|
|
|
|
Other countries | 1 (0.9) | 2 (2.0) | 0 (0) | 3 (1.0) |
|
|
| CUDITe, mean (SD) | 19.8 (5.8) | 19.7 (6.4) | 19.1 (6.2) | 19.6 (6.1) | F 2,308=0.37 | .69 | |
| SDSf, mean (SD) | 7.7 (3.5) | 7.5 (3.6) | 7.3 (3.2) | 7.5 (3.4) | F 2,308=0.37 | .69 | |
| MHI-5g, mean (SD) | 54.0 (19.3) | 53.9 (20.0) | 55.1 (22.6) | 54.3 (20.5) | F 2,308=0.11 | .90 | |
| Number of years of substance use, mean (SD) |
|
|
|
|
|
|
|
|
|
Cannabinoids | 9.6 (7.4) | 10.9 (7.6) | 12.6 (10.0) | 10.9 (8.4) | F 2,305=3.29 | .04h |
|
|
Risky alcohol usei | 2.5 (5.6) | 2.6 (5.3) | 2.7 (6.4) | 2.6 (5.7) | F 2,228=0.03 | .97 |
|
|
Cocaine | 1.1 (4.3) | 1.4 (3.8) | 0.8 (1.8) | 1.1 (3.4) | F 2,222=0.67 | .52 |
|
|
Amphetamines | 0.7 (2.0) | 1.1 (3.1) | 0.6 (2.0) | 0.8 (2.4) | F 2,208=0.91 | .40 |
| Substance use in the last 30 days, n (%) |
|
|
|
|
|
|
|
|
|
Cannabinoids | 112 (98.2) | 100 (99.0) | 93 (100) | 305 (99.0) | Not computable (no variance) | N/Aj |
|
|
Risky alcohol usei | 40 (35.1) | 26 (25.7) | 31 (33) | 97 (31.5) | χ2 2=2.6 (n=226) | .28 |
|
|
Tranquilizers | 7 (6.1) | 8 (7.9) | 5 (5) | 20 (6.5) | χ2 2=0.6 (n=215) | .74 |
|
|
Cocaine | 7 (6.1) | 14 (13.9) | 10 (11) | 31 (10.1) | χ2 2=2.7 (n=223) | .26 |
|
|
Amphetamines | 16 (14.0) | 13 (12.9) | 14 (15) | 43 (14.0) | χ2 2=0.2 (n=221) | .90 |
|
|
Hallucinogens | 6 (5.3) | 4 (4.0) | 4 (4) | 14 (4.5) | χ2 2=0.6 (n=210) | .76 |
|
|
Heroin | 0 (0) | 1 (1.0) | 0 (0) | 1 (0.3) | χ2 2=1.8 (n=201) | .40 |
|
|
Methadone | 1 (0.9) | 1 (1.0) | 3 (3) | 5 (1.6) | χ2 2=1.9 (n=197) | .40 |
|
|
Others | 4 (3.5) | 1 (1.0) | 1 (1) | 6 (1.9) | χ2 2=3.1 (n=198) | .21 |
aSelf-help with chat.
bSelf-help without chat.
cWaiting list.
dAnalysis of variance (ANOVA).
eCannabis Use Disorders Identification Test (CUDIT) scores range from 0 to 40 with a cutoff of >8 for a cannabis use disorder.
fSeverity of Dependence Scale (SDS) scores range from 0 to 15 with a cutoff of ≥4 for cannabis dependence.
gMental Health Inventory (MHI-5): higher values represent improved symptoms. MHI-5 values range from 0 to 100 with a cutoff of <70 for clinically relevant symptoms.
h P<.05, represents a significant value.
iRisky alcohol use was defined as five or more standard drinks per day on at least three days per week. A standard drink was defined as 5 cl spirits, 15-20 cl wine, or 33-45 cl beer.
jNot applicable (N/A).