Measures the 18 symptoms contained in the Diagnostic and Statistical Manual of Mental Disorders, Version IV (DSM-IV) diagnosis of Attention-Deficit/Hyperactivity Disorder. Individual item scores range from 0 (none/never or rarely) to 3 (severe/very often). Total scores range from 0 to 54.

Number of randomized participants with a value at baseline and 8 week endpoint. Last Observation Carried Forward analysis.

Measures total improvement (or worsening) of a patient's ADHD symptoms from the beginning of treatment (1=very much improved, 7=very much worsened).

Number of randomized participants with values at timepoint.

A 28-item rating scale (0 [not at all/never] to 3 [very much true/very often]) completed by the teacher to assess problem behaviors related to ADHD. Subscale total scores range from 0 to 15 for Oppositional and Cognitive Problems, 0 to 21 for Hyperactivity, and 0 to 36 for ADHD Index.

Number of randomized participants who had a value at timepoint.

Measures the 18 symptoms contained in the DSM-IV diagnosis of Attention-Deficit/Hyperactivity Disorder. Individual item scores range from 0 (none/never or rarely) to 3 (severe/very often). Total scores range from 0 to 54.

Randomized participants with a value at timepoint.

10-item parent-based scale assessing sleep problems (6 point Likert scale). Scores: Difficulty falling asleep (1-6); Quality of sleep (3-18); Functional outcome (6-36). Lower scores indicate higher problems with item. Open-ended items: Time to fall asleep (1 [0-15 minutes] to 5 [>1 hour]); Total hours (numbers associated with hours of sleep).

Randomized participants with a value at timepoint.

The ABC is a 58-item informant-based scale comprised of five subscales (Irritability [15 items], Lethargy [16], Stereotypic Behaviors [7], Hyperactivity [16], Inappropriate Speech [4]). Individual item scores range from 0 (no problem) to 3 (severe problem). Subscale scores are total of individual item scores in subscale: Irritability (0-45); Lethargy (0-48); Stereotypic (0-21); Hyperactivity (0-48); Inappropriate Speech (0-12).

Randomized participants with values at timepoint.

CSBQ is filled out by parents and consists of 49 items. Items are rated in an ordinal rather than a discrete fashion in order to establish the extent to which problems are present. The CSBQ consists of six subscales. Individual item scores range from 0=does not apply to 2=applies clearly. Total score ranges from 0 to 98.

Randomized participants with value at timepoint.

Parental distress is measured with the GHQ. The raw total score (based on 0-0-1-1 scoring system) can be used as an overall index of psychological distress, ranging from 0 to 12 with higher scores indicating more distress.

Randomized participants with value at timepoint.

The NOSI contains 123 items to be completed by the primary caregiver. Individual item scores range from 1 (completely agree) to 6 (completely disagree). Total scores range from 123 to 738.

Randomized participants with value at timepoint.

Focused attention assessed distractibility. Child needs to identify a specific target (eg, Cherry); non-target is any other fruit. Child presses "yes" when target occurs in relevant position (eg, one of vertical positions on diamond). Child presses "no" when target is absent, or when target appears on horizontal position (irrelevant target). Error rates are percentage of missing relevant targets and percentage of false alarms in response to (irr)relevant (non)targets based on number of errors/total number of trials X 100.

Number of participants with baseline and a non-missing postbaseline value at visit.

Task is the same as described in Outcome Measure #10. Reaction times (RT) for hits are mean RTs of correct responses to relevant targets. RTs for correct rejections are mean RTs for correct rejections are mean RTs for correct no responses to irrelevant targets and relevant nontargets.

Number of participants with baseline and a non-missing postbaseline value at visit.

Task is the same as described in Outcome Measure #10. Standard deviations of reaction times (RT) assess intraindividual variability in RT and refer to the same conditions as those for mean reaction times described in Outcome Measure #11.

Number of participants with baseline and a non-missing postbaseline value at visit.

The memory search task aims at measuring serial search processes to be carried out in working memory. There are 2 blocks (loads) with 40 trials each. Load 1 has 1 target to identify (e.g., an animal). A "yes" is required whenever the target is part of the displayed set of four stimuli (all animals). Load 2 has 2 targets. Whenever 1 of the targets appears in the successively displayed sets of four animals, a "yes" is required. Targets are present in 50% of trials. Error rates are the percentages of errors made in each task condition, based on the number of errors/total number of trials X 100.

Number of participants with baseline and a non-missing postbaseline value at visit.

Memory search task aims at measuring serial search processes to be carried out in working memory. There are 2 blocks (loads) with 40 trials each. Load 1 has 1 target to remember (one animal). A "yes" is required whenever the target is part of displayed set of 4 animals. Load 2 has 2 animals. A "yes" is required whenever one of the animals appears in successively displayed sets of 4 animals. Targets are present in 50% of the trials. Reaction time (RT) for hits is mean RT of correct "yes" responses to targets. RT correct rejections are mean RTs of correct "no" responses when target was missing.

Number of participants with baseline and a non-missing postbaseline value at visit.

Task is the same as described in Outcome Measure #14. Standard deviations of reaction times (RT) assess intraindividual variability in RT referring to the two conditions creating hits and correct rejections as mentioned in Outcome Measure #14.

Number of participants with baseline and a non-missing postbaseline value at visit.

A complex visuo-motor flexibility task that aims at measuring eye-hand co-ordination and fine motor control. By moving mouse cursor, the child is required to follow as closely as possible a target that randomly moves across the PC-screen. Accuracy is the mean distance between the mouse cursor and the moving target.

Number of participants with baseline and non-missing postbaseline value at visit.

A complex visuo-motor flexibility task that measures eye-hand co-ordination and fine motor control. By moving mouse cursor, the child is required to follow as closely as possible a target that randomly moves across the PC-screen. Stability is within subject variability of mean distance between cursor and target.

Number of participants with baseline and non-missing postbaseline value at visit.

Measures inhibition of pre-potent responses. 24 Go signals (open squares) are presented, randomly mixed with 24 No-Go signals (closed squares). Subjects are required to press a key if a Go signal (target) appears on the screen but to withhold a response if they see a No-Go signal. Error rate is the percentage of key presses to No-Go signals/total number of trials X 100.

Number of participants with baseline and a non-missing postbaseline value at visit.

Measures ability to neglect stimuli interfering with predefined stimulus-response coupling. Child presented with displays of 9 colored squares. Child responds to color of central square by pressing left mouse key when blue, and right mouse key when yellow. Part 1 (40 trials), surrounding squares may be same color (compatible) or different (neutral). Part 2 (80 trials), in 50% of trials, surrounding squares have color corresponding to predefined key press for other hand (incompatible). Error rates are percentages of errors in response to compatible and incompatible signals, respectively.

Number of participants with baseline and one non-missing postbaseline value at visit.

Task is the same as described in Outcome Measure #19. Mean reaction times (RTs) are computed for correct responses to compatible and incompatible flankers, respectively.

Number of participants with baseline and non-missing postbaseline value at visit.

Genotype characterization was used to determine participants' metabolic status.

All randomized participants.