Table 1 Demographic and treatment characteristics of all male participants

Age, years, mean ± SD

43.51 ± 9.82

41.60 ± 9.80

123

0.93

0.37

Daily dose, mean ± SD

74.53 ± 33.68

2.44 ± 1.81

–

Duration of MMT or BMT, mean ± SD

50.07 ± 37.86

64.47 ± 44.21

123

− 1.74

0.08

BMI, mean ± SD

23.64 ± 4.80

23.46 ± 4.23

123

0.19

0.84

Ethnic group, n (%)

 Malay

87 (91.6)

28 (90.3)

3

4.29

0.22

 Chinese

7 (7.4)

1 (3.2)

 Indian

1 (1.1)

1 (3.2)

 Others

0

1 (3.2)

Religion, n (%)

 Islam

87 (91.6)

29 (93.5)

3

1.43

0.69

 Christian

1 (1.3)

1 (3.2)

 Buddha

6 (6.3)

1 (3.2)

 Hindu

2 (2.7)

0

 Others

1 (1.1)

0

Education level, n (%)

 No education

1 (1.1)

0

3

16.55

< 0.01**

 Primary

9 (9.5)

12 (38.7)

 Secondary

75 (78.9)

19 (61.3)

 Tertiary

10 (10.5)

0

Employment, n (%)

84 (88.4)

30 (96.8)

1

1.89

0.29

Family history of drug use, n (%)

21 (23.1)

2 (6.5)

1

4.18

0.06

HBV, n (%)

4 (4.2)

0

1

1.35

0.57

HCV, n (%)

43 (45.3)

2 (6.5)

1

15.34

< 0.01**

OTI, mean ± SD

Q scores of drugs use^a

  Tobacco

12.69 ± 9.48

15.75 ± 6.21

123

− 3.23

0.001**

  Alcohol

0.01 ± 0.21

0

123

− 0.79

0.43

  Benzodiazepine

0.02 ± 0.10

0.0007 ± 0.004

123

− 1.14

0.89

  Marijuana

0.0005 ± 0.004

0

123

− 0.85

0.39

  Amphetamines

0.002 ± 0.01

0

123

− 1.41

0.16

  Heroin

0.014 ± 0.104

0

123

− 1.41

0.16

HIV risk-taking

5.16 ± 2.81

5.23 ± 2.61

123

− 0.34

0.73

Criminality

0

0

–

Social functioning^a

5.71 ± 5.34

1.65 ± 2.56

123

− 4.43

0.001**

Health^a

0.46 ± 0.80

0.10 ± 0.31

123

− 2.65

0.008**

M.I.N.I. psychiatric disorder(s), n (%)

15 (15.8)

4 (12.9)

5

8.05

0.153

 Current MDD

1 (0.8)

0

1

0.33

1

 Past history of MDD

2 (1.6)

0

1

0.66

1

 Dysthymia

1 (0.8)

0

1

0.33

1

 Panic disorder

1 (0.8)

0

1

0.33

1

 GAD

0

2 (1.6)

1

6.23

0.06

 ASD

12 (12.6)

2 (11.1)

1

0.90

0.515

Total MADRS-BM score, mean ± SD

3.11 ± 4.00

0.57 ± 1.63

103.07

− 4.22

< 0.01**