The effects of motivational interviewing on patients with comorbid substance use admitted to a psychiatric emergency unit - a randomised controlled trial with two year follow-up

Table 3 Difference in substance use the last 3 months according to time and intervention

	β^a	95% CI	p-value
Intervention compared with control at start of treatment	1.88	−1.50 to 5.22	0.271
Time 3 months compared with start of treatment ^b	−4.13	−7.17 to −1.10	0.008
Time 6 months compared with start of treatment ^b	−3.24	−6.46 to −0.02	0.049
Time 12 months compared with start of treatment ^b	−3.59	−6.85 to −0.34	0.030
Time 24 months compared with start of treatment ^b	2.37	−1.54 to 6.28	0.235
Time 3 months ^a Intervention ^c	1.18	−3.00 to 5.35	0.580
Time 6 months ^a Intervention ^c	−1.28	−5.71 to 3.15	0.571
Time 12 months ^a Intervention ^c	−1.81	−6.27 to 2.65	0.425
Time 24 months ^a Intervention ^c	−7.26	−12.64 to −1.89	0.008
Constant	11.72

Estimated days per month with 95% confidence intervals, using a linear mixed model.
^a Unstandardized regression coefficient.
^b Estimate for the control group.
^c Estimate for additional effect of time for the intervention group compared with the control group relative to start of treatment.

ISSN: 1471-244X