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Effects of Methylphenidate on Subtypes of Attention-Deficit/Hyperactivity Disorder

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ABSTRACT

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 ± 0.02 mg/kg/day = 33.06 ± 1.40 mg/day). ADHD children received a restricted arithmetic task without medication before the trial and after their noon dose on the last day of each phase. Thirty-four unmedicated controls were tested at comparable time points. Parents and teachers rated ADHD children before and after each phase of the trial; parents rated controls before the study.

Results:

Controls had marginally better arithmetic performance than children with ADHD/C who outperformed ADHD/I children. Unmedicated children with ADHD exceeded controls in task-incompatible behaviors during restricted arithmetic. Under methylphenidate, both ADHD subtypes reached control levels of arithmetic performance and task-incompatible behavior. Before the trial, parents rated children with both ADHD subtypes higher than controls on inattention, hyperactivity, and oppositionality/aggression and parents and teachers rated ADHD/C children higher than ADHD/I children on hyperactivity and oppositionality/aggression but not inattention. Methylphenidate lowered parent and teacher ratings of inattention and hyperactivity for those with both ADHD subtypes, but ratings of children with ADHD/C decreased more in hyperactivity and aggression.

Conclusions:

Methylphenidate ameliorated task-incompatible behavior, arithmetic performance, and inattention comparably in both ADHD subtypes, whereas medication reduced hyperactivity and aggression largely in children with ADHD/C.

Section snippets

ADHD Subtypes

Although the ADHD/inattentive (ADHD/I) subtype is more prevalent in the population than ADHD/combined (ADHD/C; Baumgaertel et al., 1995), ADHD/C is more common in clinical populations (Faraone et al., 1998). In addition, greater excess of boys among ADHD/C than ADHD/I children has been reported in population studies (Carlson and Mann, 2000), but not universally in clinical samples (Faraone et al., 1998). There are mixed findings concerning an excess of learning disabilities (Faraone et al., 1998

Participants

The protocol was approved by the University of Rochester's Research Subjects Review Board. Informed consent procedures were followed. We studied 19 children with ADHD/I, 22 children with ADHD/C and 34 community controls. Two additional children with ADHD children entered the pharmacological trial but withdrew during their second phase (placebo and methylphenidate, respectively) and were not included in the results. Children in all samples met these criteria: ages 6 to 12; WISC-III (Wechsler,

Analytic Strategy

Continuous variables were submitted to analyses of variance with diagnosis (or subtype, as indicated) and drug order as between-subject factors and sessions (or trial phases, as appropriate) as a within-subjects factor. For these analyses, controls were assigned to pseudo drug order groups that were comparable in age and gender, respectively, to ADHD children who received each of the drug sequences. Effect sizes are reported as η2p (partial η2). Omnibus F tests were followed by pairwise

Arithmetic

At the baseline and placebo sessions, controls exceeded children with ADHD/I in correct arithmetic solutions. There was also a nonsignificant trend for superior performance by controls over children with ADHD/C in the baseline session. Consistent with previous findings (Barkley et al., 1990, Faraone et al., 1998), no differences in arithmetic performance were obtained between the two ADHD subtypes. Notably, the arithmetic test reflects not absolute arithmetic competence, but performance at

REFERENCES (26)

  • RA Barkley et al.

    Attention deficit disorder with and without hyperactivity: clinical response to three dose levels of MPH

    Pediatrics

    (1991)
  • RA Barkley et al.

    Attention-Deficit Hyperactivity Disorder: A Clinical Workbook

    (1998)
  • VI Douglas et al.

    Short-term effects of methylphenidate on the cognitive, learning, and academic performance of children with attention deficit disorder in the laboratory and the classroom

    J Child Psychol Psychiatry

    (1986)
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    Funding was provided by National Institute of Mental Health grant MH56571.

    The authors thank Virginia Douglas, Ph.D., and Rosemary Tannock, Ph.D., for providing research instruments; Loisa Bennetto, Ph.D., for comments; H. Theresa Chang, Ph.D., Nora Ilniczky, Ph.D., and Helena Kopecky, Ph.D., for testing subjects; Chad Swenson, B.S.Pharm., for monitoring the pharmacological trial; and Thomas Olshan, B.A., Melissa Sturtz-Verastegui, B.A., and Laura Young, B.A., for scoring help.

    Disclosure: The authors have no financial relationships to disclose.

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