Effects of methylphenidate on subtypes of attention-deficit/hyperactivity disorder.

Objective: To compare the effects of methylphenidate on attention-deficit/hyperactivity disorder (ADHD) subtypes.

Method: Nineteen ADHD/inattentive (ADHD/I) and 22 ADHD/combined (ADHD/C) 6- to 12-year-old children entered a 6-week, double-blind trial of placebo and methylphenidate in divided doses (0.94 +/- 0.

Performance and private speech of children with attention-deficit/hyperactivity disorder while taking the Tower of Hanoi test: effects of depth of search, diagnostic subtype, and methylphenidate.

We administered the Tower of Hanoi to demographically comparable samples of control participants (n = 34) and children with the Combined (n = 22) and Inattentive subtypes (n = 19) of Attention-Deficit/Hyperactivity Disorder (ADHD). Controls excelled over children with the Inattentive subtype, who outperformed patients with the Combined subtype. These results replicated findings of greater executive deficits in the Combined than in the Inattentive type of ADHD.

Methylphenidate does not modify the impact of response frequency or stimulus sequence on performance and event-related potentials of children with attention deficit hyperactivity disorder.

Twenty-six children with attention deficit/hyperactivity disorder (ADHD) participated in a double-blind trial consisting of 2 consecutive weeks each of placebo and methylphenidate (M = 26.92 mg/day = 0.78 mg/kg/day).

Methylphenidate slows reactions of children with attention deficit disorder during and after an error.

A Sternberg memory search task was administered under placebo and methylphenidate to 42 children with cross-situational attention deficit disorder (ADD), 31 children with cross-situational ADD plus oppositional features, and 25 patients with marginal ADD. Overall, stimulant medication enhanced accuracy and speed. In addition, patients reacted faster on correct responses not preceded by an error than on errors (especially false alarms) or on correct responses following an error.

Clinical and cognitive effects of methylphenidate on children with attention deficit disorder as a function of aggression/oppositionality and age.

Children diagnosed with attention deficit disorder (ADD; n = 44), ADD plus aggression/oppositionality (ADD/O; n = 34), and as not meeting ADD criteria (NC; n = 29) received methylphenidate and placebo for 21 consecutive days each. Parents and teachers rated all groups improved under medication, but teachers reported less improvement for NC than for ADD/O children. Methylphenidate and chronological age had generally similar effects in a Sternberg task: greater accuracy and speed (especially for nontargets at low memory loads), larger P3b waves of event-related potentials, more pronounced slowing of P3b latency by memory load, and a greater trend of earlier peaks for targets than for nontargets.