In contrast to the United States, where middle-class parents were going down the drug route, in Scotland the condition appeared to affect disadvantaged children, although the facts were unclear.
Dr Lloyd said the rush to diagnosis was partly driven by the financial benefits for families whose children are diagnosed.
She found it difficult to accept that there was one single cause of children's difficulties when family life was going through significant changes. No one had yet looked at the effects of diet or preventative strategies or appeared to be monitoring the long-term effects.
"Families do feel blamed by schools for their children's behaviour and schools feel a loss of authority and anxiety about the level of control that exists. The label of ADHD does offer itself as a label of forgiveness and financial help but that could be too simple."
Paul Cooper, of Leicester University, a leading writer on ADHD, said the label allowed parents to remove blame and guilt and avoid the stigma of other conditions. "Most special educational needs tribunals I see these days, parents want the label and money that goes with it," Professor Cooper said.
There had to be concerns about "medication being the first choice of intervention".
Professor Cooper also sees a close correlation between exclusion south of the border, which has risen by 400 per cent in the 1990s, and the emergence of hyperactivity. "It's not that the kids' hyperactivity has caused them to be excluded, it's that the environment of the school has become less tolerant to children with those characteristics."