Table 4.

The effect of Matrix Model treatment, MPH and matrix-methylphenidate on clinical parameters in METH users ¹

Group Variable	Matrix (n = 20)	Methylphenidate (n = 22)	Matrix combination with methylphenidate (n = 21)	Control (n = 22)	P-value*	Effect size
DDQ2 Baseline	53.4 ± 6.4	53.9 ± 4.8	54.9 ± 4.5	55.9 ± 4.5	< 0.001	0.387
End-of-trial	53.7 ± 5.7a	51.2 ± 4.0	49.4 ± 5.5	56.4 ± 3.7b
P-value**	0.701	< 0.001	< 0.001	0.291
LDQ3 Baseline	21.2 ± 2.8	20.6 ± 2.6	22.3 ± 2.9	20.8 ± 2.8	< 0.001	0.226
End-of-trial	21.9 ± 2.9a	19.5 ± 2.3	19.3 ± 1.4	20.2 ± 1.6
P-value**	0.410	0.004	< 0.001	0.304
GHQ4 Baseline	31.4 ± 4.9	28.2 ± 6.6	30.9 ± 4.8	31.4 ± 5.3	0.001	0.178
End-of-trial	30.3 ± 4.2	27.6 ± 5.2	27.0 ± 5.0c	30.6 ± 5.5
P-value**	0.096	0.480	< 0.001	0.195

¹ Data are mean ± SDs

² DDQ: Desire for Drug Questionnaire

³ LDQ: Leeds Dependence Questionnaire

⁴ GHQ: General Health Questionnaire

a: Significant difference between Matrix with Methylphenidate and Matrix combination with methylphenidate groups (Bonferroni test)

b: Significant difference between Control with Methylphenidate and Matrix combination with methylphenidate groups (Bonferroni test)

c: Significant difference between Matrix combination with methylphenidate with other groups (Bonferroni test)

* ANCOVA test/ ** Paired t-test