[Hyperactivity at 18 months of age and attention-deficit hyperactivity disorder before entry to school--follow up study from 18 months to 6 years].

Forty children with the following behavior characteristic were selected by observing the attachment behavior between them and their parents at the time of developmental exam in a 18 months' health checkup. The behavior in question is; 18 month old children scurry away from their parent without looking back on parent's calls and without confirming parent's positions. Then all the examined 978 children including the children who had shown the above scurrying away behavior were prospectively followed until before the entry to school. At age six, 6 children were diagnosed of Mental Retardation, 4 of Pervasive Developmental Disorder, and 28 of Attention-Deficit Hyperactivity Disorder (ADHD). Now these results (especially the relationships between this scurrying away behavior at 18 months and ADHD before the entry to school) were analyzed statistically and discussed, then the next conclusions were derived. 1. This scurrying away behavior, especially the behavior without confirming parent's positions, is significantly related to ADHD before the entry to school. 2. This scurrying away behavior is one of the characteristic behaviors at 18 months in ADHD and corresponds to hyperactivity at 18 months. 3. The conduct of throwing a toy block is one of the behaviors that indicates impulsivity at 18 months, when children are requested to hand over a toy block in the developmental exam. 4. Through behavioral observation, ADHDs before the entry to school are categorized to 3 subtypes by presence or absence of this scurrying away behavior at 18 months or by presence or absence of aggressivity before the entry to school. 5. Among the 3 subtypes, the type with this scurrying away behavior and aggressivity before the entry is most necessary to be treated continuously from early childhood. Because it has impulsivity and speech delay since 18 months and untreatable behavioral problems in day nurseries or kindergartens, and therefore it might have Conduct Disorder or Learning Disorder in the future.