Preschoolers Tolerate Methylphenidate
Adverse events were well tolerated in a majority of 3− to 5-year-olds who took methylphenidate for ADHD, based on data from 183 children, said Tim Wigal, Ph.D., of the University of California, Irvine, and his colleagues.
Although methylphenidate's safety had been studied in school-aged children, studies of its effects on preschoolers are limited, they noted.
Overall, 21 (11%) of the 183 children discontinued as a result of adverse events that were rated moderate to severe. During the initial treatment and randomized study phases, nine children discontinued the study because of emotionality/irritability and one each discontinued because of tics, tactile hallucinations, possible seizure, rash, and insomnia (J. Am. Acad. Child Adolesc. Psychiatry 2006;45:1294–303).
Adverse effects associated with discontinuation during the maintenance phase of the study included appetite loss, irritability, tics, weight loss, depression, anxiety, and social isolation. No cardiovascular-related adverse events were reported in any of the study phases.
The 11% rate of adverse events in this study of preschoolers is high, compared with the rates of less than 1% that have been reported among school-aged children. Rates of the most common adverse events, however, including irritability and emotionality, decreased significantly during the maintenance phase, which suggests that young children's tolerance of methylphenidate may improve with time, the researchers said.
Dr. Wigal has received financial support from several companies that manufacture and market methylphenidate, including Cephalon, Eli Lilly & Co., McNeil, and Shire.
ADHD and Tourette's: All in the Family
Tourette's disorder and ADHD may not have the same genetic cause, but cases in which the two conditions occur comorbidly tend to run in families, said Dr. S. Evelyn Stewart of Harvard University, Boston, and her associates.
To determine the possible connection between ADHD and TD in families, Dr. Stewart and her colleagues interviewed 239 patients aged 7–18 years and 692 relatives of various ages. The patients were divided into four case groups: 75 individuals with comorbid ADHD and TD, 74 with TD only, 41 with ADHD only, and 49 controls (J. Am. Acad. Child Adolesc. Psychiatry 2006;45:1354–62).
Comorbid rates of ADHD and TD were significantly higher among relatives of patients in all four case groups, compared with either condition alone. The age-corrected rates of ADHD were significantly higher in relatives with TD than in relatives without TD (48% vs. 13%). Similarly, the rates of TD were significantly higher among relatives with ADHD than in relatives without ADHD (27% vs. 5%). The ages of onset for ADHD and TD were not significantly different in relatives among the four case groups.
The presence of either the combined or the inattentive subtype of ADHD was a significant predictor of TD in relatives of study patients in all the case groups. Also, most cases of ADHD in relatives of study patients with TD were either the combined or the inattentive subtypes, suggesting that TD symptoms were probably not misdiagnosed as ADHD, the researchers noted.
Externalization in Daytime Wetters
Children aged 7–9 years who wet their pants during the day have significantly more parent-reported psychological problems than do children with no daytime wetting, based on data collected from 8,213 children as part of a longitudinal study.
The clinical implication is that early intervention for children who have frequent problems with daytime wetting may prevent psychological problems once they start school, reported Carol Joinson, Ph.D., of the University of Bristol (England).
Overall, 643 children (7.8%)–291 boys and 352 girls–reported daytime wetting, based on a parent questionnaire (Pediatrics 2006;118:1985–93). Children with daytime wetting were twice as likely as those with no daytime wetting to demonstrate attention and activity problems (24.8%), oppositional behavior (10.9%), and conduct problems (11.8%).
An adjustment for developmental delay, which was identified in 276 children, significantly reduced the odds of oppositional behavior or attention and activity problems, but there was still a strong association between these problems and daytime wetting. An adjustment for comorbid soiling also reduced the odds ratios for externalizing behavior problems, but an independent association persisted, the researchers noted.
The rate of externalizing problems (attention/activity problems, oppositional disorder, and conduct disorder) was higher in the 82 (12.8%) children whose severe daytime wetting met the DSM-IV criteria.