Table S1.

ANCOVA analysis of change from baseline to end point in ADHD-RS-IV total score by prior stimulant use in the RCT (LOCF; full-analysis set)

Test vs comparator	LS mean (SE)* test	LS mean (SE)* comparator	Difference in LS mean treatment – comparator (95% CI)	Effect size (95% CI)	P-value
Any prior stimulant†
GXRa vs placebob	−23.283 (1.6703)	−13.295 (1.6031)	−9.988 (−14.369 to −5.608)	0.86 (0.47 to 1.26)	<0.001
ATXc vs placebob	−15.297 (1.6517)	−13.295 (1.6031)	−2.002 (−6.347 to 2.344)	0.17 (−0.20 to 0.55)	0.365
Stimulant-naïve
GXRd vs placeboe	−24.400 (1.5514)	−16.835 (1.6211)	−7.564 (−11.802 to −3.327)	0.66 (0.28 to 1.03)	<0.001
ATXf vs placeboe	−21.887 (1.5784)	−16.835 (1.6211)	−5.052 (−9.344 to −0.759)	0.44 (0.06 to 0.81)	0.021

Notes:

^*A negative difference in LS mean (active treatment – placebo) indicates a positive effect of the active treatment over placebo;

^†includes both prior MPH and prior non-MPH subgroups. Number of observations per group at visit 15:

^a52,

^b56,

^c54,

^d60,

^e55, and

^F58.

Abbreviations: ADHD-RS-IV, Attention-Deficit/Hyperactivity Disorder Rating Scale version IV; ANCOVA, analysis of covariance; ATX, atomoxetine; CI, confidence interval; GXR, guanfacine extended release; LOCF, last observation carried forward; LS, least squares; MPH, methylphenidate; SE, standard error; RCT, randomized controlled trial.