Primary Outcome Measures:
- TOVA-CPT (Test of Variables of Attention) [ Time Frame: Change from baseline to endpoint at 12 weeks. ] [ Designated as safety issue: No ]
Secondary Outcome Measures:
- BRIEF; Conners Parent Rating; Paired Assoc. Test; WC Math/Decision Speed; Trails. [ Time Frame: Change from baseline to endpoint at 12 weeks. ] [ Designated as safety issue: Yes ]
The subject and the parent/legal guardian will take part in a screening visit to establish eligibility, and will give informed consent to participate in the study. The parent/legal guardian will be interviewed about the subject's medical history, education status, and medications being taken. The subject and the parent/legal guardian will be given several tests to assess the subject's attention, intelligence, and motor performance skills. A standard set of non-invasive medical examinations and tests will be performed. These interviews and tests will determine whether or not the subject may be eligible to participate.
The eligible subject and his/her parent/legal guardian will come back to the clinical center on the day that the subject is to begin participation in the study. The subject's attention skills will be tested, and the parent/legal guardian will provide related information to the clinic. Vital signs will be assessed. At random, the subject will be assigned to receive either the active drug or placebo, once daily at approximately the same time every day. The study will be "double-blind", meaning that the clinical staff, the subject, and the parent/legal guardian will not know whether the subject is taking active drug or placebo. The parent/legal guardian will be given enough of the study drug or placebo to last for 6 weeks. Doses of active drug will be adjusted according to the subject's body weight.
Three weeks following the baseline visit, the clinic will follow-up by phone to the parent/legal guardian. At 6 and 12 weeks after the subject has started taking the study drug, the subjects and parent/legal guardian will come to the clinic for tests and interviews similar to those at the first visit to the clinic. The parent/legal guardian will receive new supplies of the study drug at each of these clinic visits.
At the time of the 12-week visit, all subjects who had been taking placebo will start taking the active drug and will continue to do so for the remainder of the study, which will last for a total of 24 weeks. The period between 12 and 24 weeks is referred to as the "blinded extension" phase. The subjects who had been taking active drug will continue to do so. At 15 weeks after the subject started taking study drug (3 weeks after all subjects taking placebo are switched to the active drug), another telephone call will be made by the clinic to the parent/legal guardian. At 18 and 24 weeks, the subject and the parent/legal guardian will return to the clinic for tests similar to those at the visits which took place at 6 and 12 weeks. The subject's participation in the study will end at the conclusion of the 24-week visit.
A small amount of blood may be drawn from some subjects during the 12-week, 18-week, and 24-week visits to measure the amount of active drug that is in the subject's bloodstream.