Methylphenidate dosing: twice daily versus three times daily

OBJECTIVE

To evaluate the short-term efficacy and side effects associated with two methylphenidate hydrochloride (MPH) dosing patterns.

METHODS

Twenty-five boys with attention deficit hyperactivity disorder (ADHD) participated in a 5-week, triple-blind, placebo-controlled, crossover evaluation of MPH administered twice (b.i.d.) versus thrice (t.i.d.) per day (mean dose = 8.8 +/- 5 mg, .30 +/- .1 mg/kg/dose). Four dosing conditions (placebo, titration [gradual increase to target dose], b.i.d., and t.i.d.) were used. Dependent measures obtained on a weekly basis included: parent and teacher ratings of child behavior, parent-child conflicts, parent report of stimulant side effects, child self-report of mood symptoms, a sleep log, laboratory measures of attention, and actigraphic recording of sleep activity.

RESULTS

All dosing conditions resulted in significant effects on ADHD symptoms when compared with baseline. Relative to placebo, t.i.d. dosing was characterized by improvement on the greatest number of behavioral measures, and both b.i.d. and t.i.d. were generally more effective than titration. Direct comparisons of b.i.d. and t.i.d. dosing revealed that t.i.d. was associated with greater improvement on the Conners Parent Rating Scale Impulsivity/Hyperactivity factor, with a similar marginally significant effect for the ADD-H Teacher Rating Scale Hyperactivity factor. The analysis of clinically significant change favored a three-times-a-day dosing schedule over placebo on both parent and teacher ratings of impulsivity/hyperactivity and attention. Compared with placebo, appetite suppression was rated, on average, as more severe in the t.i.d. and titration conditions, but not in the b.i.d. condition. However, the number of subjects who exhibited any or severe appetite suppression did not differ significantly between the b.i.d. and t.i.d. schedules. Although there was no difference in sleep duration for children on b.i.d. and t.i.d. schedules, total sleep time appeared to decrease slightly on t.i.d. relative to placebo according to both parent ratings and actigraphic assessment. There were no significant differences between b.i.d. and t.i.d. on any other side effects or sleep variables.

CONCLUSIONS

For many children with ADHD, t.i.d. dosing may be optimal. There are few differences in acute side effects between b.i.d. and t.i.d. MPH dosing. The dosing schedule should be selected according to the severity and time course of ADHD symptoms rather than in anticipation of dosing schedule-related side effects.

Adaptive skills dysfunction in ADD and ADHD children

Adaptive functioning was examined in children with Attention Deficit Hyperactivity Disorder (ADHD) or Attention Deficit Disorder (ADD), and a psychiatric comparison group of children with pervasive developmental disorders or mild mental retardation (PDD/MR). As assessed with the Vineland Adaptive Behavior Scales, adaptive functioning was well below average for all three clinic groups. (The PDD/MR group had the lowest adaptive functioning scores, although not statistically different from the other groups). However, the level of adaptive functioning relative to IQ in the areas of Socialization, Communication and Daily Living was significantly lower for the ADD and ADHD groups. These deficits in adaptive functioning that characterize children with ADHD and ADD may help explain the poor long-term prognosis of ADHD, suggesting that increased attention should be paid to the assessment and treatment of adaptive functioning in individuals with ADHD and ADD.

Psychometric characteristics of the Wender Utah Rating Scale (WURS): reliability and factor structure for men and women

The goals of this study were to examine the factor structure of the Wender Utah Rating Scale (WURS), to evaluate potential gender differences in factor composition, and to assess the reliability of the scale. The WURS was completed by 310 fathers and 305 mothers of children referred for evaluation of Attention-Deficit Hyperactivity Disorder (ADHD). For males, a five-factor solution (Conduct Problems, Learning Problems, Stress Intolerance, Attention Problems, Poor Social Skills/Awkward) accounted for 72 percent of the variance. There was also a five-factor solution for females (Dysphoria, Impulsive/Conduct, Learning Problems, Attention and Organizational Problems, Unpopular) which accounted for 71 percent of the variance. Symptoms of inattention and impulsivity loaded on separate factors for both men and for women. Test-retest reliability was examined with a different sample of 57 adults who completed the WURS on two separate occasions, 1 month apart. The WURS demonstrated satisfactory internal consistency and temporal stability, and it may be a useful tool for the study of ADHD in adults.

Psychometric properties of the children's atypical development scale

The Children's Atypical Development Scale (CADS) is a 53-item rating scale designed to measure unusual behaviors in children. Principal-factor analysis on a clinic-referred and pediatric sample of 474 children resulted in a four-factor solution: Communication Deficits, Lability, Social Relatedness Deficits, and Preoccupation. The CADS is internally consistent and has adequate temporal stability. CADS factor scores were differentially associated with parent and teacher rating scales, IQ, and Continuous Performance Test errors. The scale shows promise as a clinical and research tool for assessing atypical behaviors associated with pervasive developmental disorder and other neurobehavioral disorders.