Table 4.

Prospective Linear mixed model results (N=109) of the effect of: a) PR/NR status on PDA over time (above); and, b) PR/NR status on PDA over time co-varying for all variables that significantly predicted outcomes at treatment intake (below)

Variable	B	SE	df	t	p
Intercept	44.222	4.892	107	9.04	0.000
PR/NR status	3.953	6.707	107	0.59	0.557
Time	−0.265	1.539	290	−0.17	0.864
Time (quadratic)	0.018	0.112	290	0.16	0.872
Time* PR/NR status	3.597	2.142	290	1.68	0.094
Time (quadratic)* PR/NR status	−0.304	0.156	290	−1.95	0.052

Variable	B	SE	df	t	p
Intercept	31.812	7.415	97	4.29	0.000
PR/NR status	−5.738	6.249	97	−0.92	0.361
Time	−1.180	1.620	287	−0.73	0.468
Time (quadratic)	0.081	0.116	287	0.70	0.487
Time* PR/NR status	3.867	2.247	287	1.72	0.088
Time (quadratic)* PR/NR status	−0.322	0.160	287	−2.01	0.047
Prior outpatient treatment	4.154	5.848	97	0.71	0.479
Prior inpatient treatment	4.603	6.259	97	0.74	0.464
Past 90 days 12-step attendance	21.774	6.380	97	3.41	0.001
Motivation for abstinence	−0.231	0.862	97	−0.27	0.789
Abstinence self-efficacy	0.809	0.889	97	0.91	0.365
Abstinence-focused coping	2.177	1.974	97	1.10	0.273

PR=Positive Reinforcement group; NR=negative reinforcement group; M= mean; SE= standard error; df= degrees of freedom; B=standardized partial beta coefficient; p= probability/significance level