["Early" diagnosis and "early" intervention in children with mental retardation--when is early enough to diagnose them?].

Patients with mental retardation (MR) cannot always be diagnosed accurately by physicians who are specialized in child neurology and/or developmental disorders at their first visit to the clinic. Precise examination such as psychological tests and chromosomal analysis are often necessary to diagnose them. Some patients with autistic disorders without MR often are misdiagnosed as having MR. Patients with mild to moderate MR are sometimes diagnosed late in their late teens or twenties. Timely diagnosis and timely/continuous intervention is more important than early diagnosis and early intervention for the mentally retarded.