MISDIAGNOSED CASES OF ADHD: RESULTS OF A QUESTIONNAIRE TO CHILD NEUROLOGISTS

Objectives: The symptoms of ADHD, hyperactivity, inattention and impulsivity are also common in other physical and/or neurological diseases. Therefore, not only psychiatric disorders but also physical and/or neurological diseases play an important role for the differential diagnosis of ADHD. The objective of this study is to collect the information about physical and/or neurological diseases as a factor in the differential diagnosis of ADHD.

Methods: A Questionnaire study was carried out among 951 child neurologists in Japan, and information on misdiagnosed cases of ADHD was collected.

Results: Questionnaires were returned by three hundred and nine (32.5%) of the child neurologists surveyed. Fifty three of them (17.2%) had experiences with a total 60 patients with physical and/or neurological disease misdiagnosed as ADHD. Nineteen of these 60 cases (31.7%) were epilepsy, 10 (16.7%) were metabolic or degenerative disorders (adrenoleukodystrophy, metachromatic leukodystrophy, etc.), 7 (11.7%) were hyperthyroidism, 5 (8.3%) were brain tumors. In particular especially frontal lobe epilepsy was frequently misdiagnosed as ADHD. Their chief complaints were hyperactivity (77.4%), less concentration (62.3%) and academic underachievement (47.2%). The time lag until given an accurate diagnosis was variable, –24.5% was less than two weeks, 41.5% less than one month and 20.8% more than several months. Most reliable examinations toward an accurate diagnosis involved EEG and CT/MRI. Detailed interviews of patient histories were also very reliable.

Conclusions: Many psychiatric disorders have been nominated for differential diagnosis of ADHD, but less information exists for physical and/or neurological diseases. Now we know that epilepsy, leukodystrophy, hyperthyroidism and brain tumors should receive more attention for differential diagnosis of ADHD.