LONDON, Sept. 9 (UPI) -- The so-called "bad behavior syndrome" is a serious childhood disease that increases the risk of later mental illness, British doctors say.
Researchers say there is mounting evidence attention deficit hyperactivity disorder, or ADHD, affects between 1 percent and 5 percent of school-age children, the Telegraph of London said.
A chaotic or difficult home environment in the early years was seen as a possible contributing cause.
But Eric Taylor, an ADHD expert at the Institute of Psychiatry in London, dismissed accusations the condition was a fiction of drugs companies, or often little more than bad behavior in children. However, drugs companies may have contributed to overuse of medication in America, he said.
A study by Taylor found hyperactive children were four times more likely than normal children to suffer from mental illness as young adults.
Although many of the hyperactive children developed into healthy teenagers, 35 percent had mental disorders.
