Table 2. Correct-answers, omission, action and reaction time measures on tests for selective, divided and sustained attention.

	Methylphenidate				F	P
	Placebo	10 mg	20 mg	40 mg
Selective attention
Correct	19.44 ± 3.81	21.44 ± 2.12	20.11 ± 2.47	20.00 ± 3.12	0.74	0.53
Omission	3.88 ± 3.75	1.66 ± 2.44	3.11 ± 2.57	3.77 ± 3.89	0.89	0.45
Action	1.88 ± 1.9	1.33 ± 1.41	1.11 ± 1.26	1.66 ± 1.93	0.39	0.75
Reaction time	0.461 ± 0.03	0.456 ± 0.02	0.468 ± 0.02	0.467 ± 0.04	0.26	0.84
Divided attention
Correct	21.55 ± 0.72	21.44 ± 0.72	21.88 ± 0.33	21.77 ± 0.44	2.95 (H)	0.39
Omission	1.66 ± 0.86	1.66 ± 0.7	1.55 ± 0.52	1.44 ± 0.52	0.22	0.87
Action	1.55 ± 0.88	2.22 ± 1.48	1.22 ± 0.66	1.44 ± 1.13	1.42	0.25
Reaction time	0.620 ± 0.08	0.627 ± 0.1	0.599 ± 0.05	0.590 ± 0.06	0.43	0.73
Sustained attention
Correct	64 ± 0	64 ± 0	64 ± 0	64 ± 0
Omission	0 ± 0	0 ± 0	0 ± 0	0 ± 0
Action	0.11 ± 0.33	0.11 ± 0.33	0.44 ± 1.01	0.11 ± 0.33	0.73	0.53
Reaction time	0.349 ± 0.04	0.347 ± 0.08	0.343 ± 0.03	0.331 ± 0.05	0.16	0.92