There is no objective investigation for ADHD such as a blood test or a brain scan. The key symptoms of hyperactivity, inattention and impulsiveness are inherently ambiguous; achieving a diagnosis can sometimes tell you as much about the clinician as the patient. And we know that what happens in the US is usually a foretaste of what will happen here, so it's particularly worrying that 7 per cent of American children between 6 and 11 have been diagnosed with ADHD. Ritalin consumption across the Atlantic has also increased more than six-fold in the past decade and is now at record levels.
Debate rages about why ADHD rates are going up. One possible explanation is that the disorder has become more apparent now that Ritalin is seen as an effective treatment. What would be the point of going to the doctor if he or she couldn't do much for you?
Ilina Singh points out that parents may prefer a medical diagnosis as it implicitly absolves them of blame. Biologically oriented accounts shift responsibility away from poor parenting; "brain-blame" rather than "mother-blame". Historically, before more modern, biological accounts arose, mothers were primarily implicated in psychological disorders as diverse as schizophrenia (the "schizophrenogenic mother"), autism, epilepsy and asthma.
Singh found that mothers' discussion of their sons' problems (ADHD affects boys more than girls) often centred on the lack of assignable blame, and the importance of separating the boy from "the problem". As one mother said: "It's not his problem, it's his brain's problem"; and another, echoing a phrase clinicians use to explain ADHD: "It's his behaviour that's the problem, not him". Singh refers to this as the "no-fault" response.
But there is a danger that none of us takes responsibility for behaviour.
Instead we will point the finger at the pharmacologist for not giving our child the right pill quickly enough.
Dr Raj Persaud is consultant psychiatrist at the Maudsley Hospital in south London. His latest book is The Motivated Mind (Bantam Press). Email: email@example.com