In a randomized, double-blind, placebo-controlled study of 60 children aged 8-12 years with ADHD treated with two doses of methylphenidate (MPH), 0.25 and 0.5 mg/kg, and placebo, a linear improvement was obtained at both doses in alertness and focused and sustained attention. No significant improvement occurred for divided attention. Intensity-dimension functions are best influenced by higher doses, executive functions by moderate doses, and selective-dimension functions by variable doses. Responders defined by improved behavior did not differ from nonresponders. 
COMMENT. Multiple indices of efficacy should be monitored during treatment of ADHD, and the dosage of MPH selected according to the targeted area, inattention or hyperactivity-impulsivity. The clinical practice of determining response to stimulant therapy from parent or teacher rating may not be sufficient, and measures of several components of attention (sustained, focused, divided, stop-signal paradigm) should be considered when practical and available.
Antihistamine side-effects in children with allergic rhinitis. Antihistamines are frequently taken by children with ADHD and are sometimes considered to aggravate the symptoms. Cetrizine 10 mg, a second-generation antihistamine, increased P300 latency and had a sedative effect without a significant change in subjective somnolence, as measured by a visual analog scale . Repeated dosing may be found to adversely affect attention, and antihistamines should be considered a potential risk factor for impaired learning.