Table 2 Group demographics

Age, mean of years at T1 (SD)

29.2 (6.8)

27.7 (6.8)

28.7 (9.6)

M vs. BN, p = 0.99

M vs. NC, p = 0.99

BN vs. NC, p = 0.99

Sex: females/males

7/6

4/11

8/7

M vs. BN, p = 0.14

M vs. NC, p = 0.98

BN vs. NC, p = 0.14

Verbal intelligence, Mean^b (SD)

100.6 (11.4)

99.4 (9.3)

104.1 (9.6)

M vs. BN, p = 0.99

M vs. NC, p = 0.74

BN vs. NC, p = 0.63

Education, mean of years (SD)

10.1 (1.2)

10.5 (2.0)

12.6 (1.3)

M vs. BN, p = 0.54

M < NC***, p < 0.001

BN < NC**, p = 0.006

Opioid of abuse used within last month at T1

   Buprenorphine

85%

100%

-

M vs. BN, p = 0.48^c

   Heroin

15%

0%

Other substances of abuse used within last month at T1 and T2

   Alcohol (heavy use)^d

15%/15%

13%/7%

7%/7%

M vs. BN vs. NC (T1/T2),

p = 0.99^c/0.99^c

   Amphetamine

8%/8%

13%/7%

-

M vs. BN vs. NC (T1/T2)

p = 0.99^c/0.99^c

   Benzodiazepine, any Use

100%/100%

100%/100%

0%/0%

M & BN > NC*** (T1/T2),

p < 0.001^c/p < 0.001^c

   Benzodiazepine, extra doses

38%/38%

42%/33%

-

M vs. BN (T1/T2),

p = 0.62/p = 0.78^c

   Cannabis

31%/31%

40%/27%

-

M vs. BN (T1/T2),

p = 0.83^c/0.84^c

   Nicotine (daily use)

100%/100%

100%/100%

33%/33%

M & BN > NC*** (T1/T2),

p < 0.001^c/p < 0.001^c

Duration of OST in the day of testing at T1, Mean of days (SD)

21 (14)

19 (12)

-

M vs. BN, p = 0.69

Duration of OST on the day of testing at T2, Mean of days (SD)

213 (25)

224 (17)

-

M vs. BN, p = 0.15

Participants with other dependence or abuse diagnosis at T1

   Alcohol

0%

0%

0%

M vs. BN vs. NC, p = 0.99^c

   Amphetamine

0%

0%

-

M vs. BN, p = 0.99^c

   Benzodiazepine

100%

100%

-

M vs. BN, p = 0.99^c

   Cannabis

15%

20%

-

M vs. BN, p = 0.99

   Nicotine

100%

100%

33%

M vs. BN, p = 0.99^c

M vs. NC, p = 0.13^c

BN vs. NC, p = 0.12^c

Participants with any DSM-IV axis I diagnosis at T1

15%

20%

0%

M vs. BN, p = 0.99^c

M vs. NC, p = 0.21^c

BN vs. NC, p = 0.22^c

Participants with any personality disorder diagnosis (DSM-IV axis II) at T1

54%

59%

0%

M vs. BN, p = 0.99^c

M > NC**, p = 0.003^c

BN > NC**, p = 0.002^c

Duration of opioid abuse at T1, Mean of years (SD)

11.4 (5.5)

9.0 (2.9)

-

M vs. BN, p = 0.26

Duration of any substance abuse at T1, Mean of years (SD)

15.0 (5.1)

13.4 (5.2)

-

M vs. BN, p = 0.37