The cognitive and behavioral problems and effects of treatment of attention deficit hyperactivity disorder (ADHD) in 20 children with NF1 and ADHD were compared to 26 control children with NF1, 14 controls with ADHD, and 14 controls with normal development, studied at Klinikum Nord Ochsenzoll. Hamburg, Germany. Of 93 children with NF1 followed at the clinic, 46 had ADHD. Among the 4 groups, children with NF1 and ADHD had the lowest IQ scores. Tests of Variables of Attention (TOVA) scores were lower in the NF1/ADHD and ADHD control groups than in the non-ADHD groups. Scores on the Child Behavior Checklist (CBCL) were significantly poorer for the NF1/ADHD group than the NF1 control group. Low dose (5-15 mg) methylphenidate administered to the NF1/ADHD group significantly improved TOVA scores and CBCL scores. 
COMMENT. NF1 is associated with a 50% incidence of ADHD, and learning and social problems in children with NF1 are correlated with ADHD. Stimulant medication in children with NF1/ADHD may improve their cognitive, attention, impulsive, and social problems.