SAN DIEGO – Preschool children with attention-deficit hyperactivity disorder who had three or more comorbid disorders responded less favorably to 5 weeks of methylphenidate treatment, compared with children who had fewer comorbid disorders, according to the results of a randomized study.
Dr. Jaswinder K. Ghuman reported the findings of a secondary analysis of the National Institute of Mental Health Preschool and Treatment Study (PATS) at the annual meeting of the American Academy of Child and Adolescent Psychiatry.
Dr. Ghuman and her associates examined baseline characteristics of methylphenidate treatment response in 165 children aged 3.5–5 years who were randomized to methylphenidate over a 5-week period. The doses ranged from 7.5 mg/day to 22 mg/day.
Of the 165 children, 47 (28%) had no comorbid disorder, 69 (42%) had two comorbid disorders, and 15 (9%) had three to four comorbid disorders, reported Dr. Ghuman, who directs the infant and preschool program in the division of child and adolescent psychiatry at the University of Arizona in Tucson.
Oppositional defiant disorder was the most common comorbid disorder, followed by communication disorders and anxiety disorder.
She and her associates found that study participants who had three or more comorbid disorders responded less favorably to 5 weeks of methylphenidate treatment, compared with those who had two, one, or no comorbid disorders.
They also found no evidence that age, ethnicity, gender, intelligence quotient, ADHD subtype and severity, or the mother's education level influenced treatment outcome.
In a separate presentation at the meeting, Howard Abikoff, Ph.D., discussed a subset analysis of 114 children in the PATS who improved with methylphenidate treatment. Of the 114 children, 61 received methylphenidate and 53 received placebo over a period of 4 weeks.
He and his associates compared the two groups of children to see whether the methylphenidate improved children's social skills, classroom behavior, and ratings of parenting stress.
At baseline and at week 4, the investigators administered the Strengths and Weaknesses of ADHD Symptoms and Normal Behavior (SWAN) scale, the Social Competence Scale (SCS), the Parenting Stress Index (PSI), and the Clinical Global Impression-Severity (CGI-S) scale.
Of the 114 children, 24 in the placebo group and 9 in the treatment group dropped out because their behavior deteriorated, said Dr. Abikoff, who directs the Institute for Attention Deficit and Hyperactivity and Behavior Disorders at New York University, New York. Two others declined study participation and one had medication-related side effects, resulting in a total of 36 children who dropped out of the study.
Dr. Abikoff reported that the placebo and treatment groups did not differ significantly in the parents' ratings for the SWAN, SCS, and PSI, or in the SWAN teacher ratings. However, the children's teachers rated children in the treatment group as significantly improved on the SCS, compared with their peers in the placebo group.
“The teachers were picking up something,” Dr. Abikoff said at the meeting. “Is that because teachers had an opportunity to judge a child's social functioning, compared to hundreds of other children they've worked with, and also because they're seeing that child interact with many children day in and day out, whereas parents are limited in what they're able to see?”
He also noted that results of the clinician CGI-S ratings showed significantly more improvement among children in the treatment group, compared with those in the placebo group.
Dr. Abikoff said the findings underscore “the need for multiple informants when you're working with children with ADHD, regardless of their age, but certainly when they're in the preschool range.