Table 1 Sample characteristics: demographic variables

Mean age (SD)

42.3 (9.0)

42.6 (8.4)

41.9 (10.0)

t (33) = 0.21, p = .84

Gender, n (%)

χ² (1, N = 34) = 0.012, p = .92

Male

23 (67.6)

13 (68.4)

10 (66.7)

Female

11 (32.4)

6 (31.6)

5 (33.3)

Ethnicity, n (%)

χ² (4, N = 34) = 2.962, p = .56

Dutch

23 (67.6)

13 (68.4)

10 (66.7)

European (other)

2 (5.9)

1 (5.3)

1 (6.7)

Arabic/ Moroccan/ Turkish

4 (11.8)

1 (5.3)

3 (20.0)

Black/ Surinamese/ Caribbean

4 (11.8)

3 (15.8)

1 (6.7)

Other

1 (2.9)

1 (5.3)

0 (0)

Education (certificate), n (%)

χ² (3, N = 34) = 0.404, p = .94

No education, primary school

11 (32.4)

6 (31.6)

5 (33.3)

Secondary school, lower level

8 (23.5)

4 (21.1)

4 (26.7)

Secondary school, higher level

9 (26.5)

5 (26.3)

4 (26.7)

Postsecondary

6 (17.6)

4 (21.1)

2 (13.3)

Relationship status, n (%)

χ² (2, N = 34) = 2.859, p = .24

Single

31 (91.2)

17 (89.5)

14 (93.3)

Partner

2 (5.9)

2 (10.5)

0 (0)

Missing

1 (2.9)

0 (0)

1 (6.7)

Source of income, n (%)

χ² (2, N = 34) = 3.026, p = .22

No work

22 (64.7)

10 (52.6)

12 (80.0)

Work

11 (32.4)

8 (42.1)

3 (20.0)

Missing

1 (2.9)

1 (5.3)

0 (0)

Dropouts, n (%)

SUD treatment & SWT

13 (38.2)

9 (47.4)

4 (26.7)

χ² (1, N = 34) = 1.521, p = .30

SUD treatment

12 (35.3)

8 (42.1)

4 (26.7)

χ² (1, N = 34) = 0.875, p = .48

Baseline Measures

Mean PDS (SD)

29.5 (10.0)

30.4 (9.7)

28.3 (10.7)

t (33) = 0.62, p = .54

Mean TLFB (SD)

20.0 (27.2)

19.9 (29.3)

20.1 (25.4)

t (33) = 0.19, p = .99