Is clinic prevalence of ICD-10 hyperkinesis underestimated? Impact of increasing awareness by a questionnaire screen in an UK clinic.

Hyperactivity is common, but its diagnosis is still controversial, with two contending approaches: ADHD from DSM IV and hyperkinesis from ICD-10. The concept of ADHD predicts higher rates, but its use may lead to overmedication. Hyperkinesis usefully indicates medication, but clinics using it may detect many fewer cases, raising the possibility of underdiagnosis. It has never been shown whether this lower rate results from hyperkinesis' criteria, or to the differing methods used to detect hyperactivity in those centres that prefer it. We report a mirror study, examining rates of all types of hyperkinesis before and after the introduction of a preliminary screen (not originally intended to detect hyperkinesis). Its introduction resulted in an increase of detected hyperkinesis from 2% to 25% of the clinic sample with no change in diagnostic criteria. This was independent of any other change in the sample or clinic staff. We conclude that insensitive assessment may be responsible for low rates of diagnosis of ICD-10 hyperkinesis in secondary care clinics.