No one would deny that drug abuse is a serious problem in today's school system. Eleven per cent of 11 to 15-year-olds use cigarettes, 22 per cent alcohol, 12 per cent cannabis, 7 per cent volatile substances such as glue and 4 per cent Class A drugs such as heroin1. In general, these numbers have remained unchanged since 2000.
But just as worrying as these illicit drugs is the growing crisis with their prescribed counterparts such as methyl-phenidate (eg Ritalin), which is used to treat attention deficit hyperactivity disorder (ADHD), and antidepressants such as Fluoxetine.
It can be difficult to get reliable figures, but we can estimate that 1 to 2 per cent of children in England are taking methylphenidate - and the trend seems to be growing fast.
The Government's figures show the number of methylphenidate prescriptions increased 60-fold in the decade to 2004 and doubled between 2000 and 2004, to 360,000. We need to get the balance right between ensuring that those children who need medication receive it, and avoiding a pharmaceutical quick fix or behavioural panacea.
Despite much research in this area, it is still unclear why the number of children who are being medicated with psychoactive drugs is on the increase.
It is clear that the brains of children develop to prepare them for life in the context in which they find themselves. This adaptability of the brain is one of its great strengths. Some of the many and varied influences upon the developing mind in the modern world, such as the increasing immersion in screen culture, may be the same influences which cause a rise in the incidence of depression, hyperactivity and deficits in attention. Or it may be that behaviour now deemed unacceptable was once thought of as normal: that we are now prescribing drugs for children who would once have been thought merely boisterous or over-exuberant.
It is difficult to determine whether the number of children with mental health disorders is increasing or if the cultural goalposts are moving. Of course, explaining the rise in the prescription of psychoactive drugs in one of these two ways clearly over simplifies the situation. They are neither mutually exclusive nor exhaustive. But there is clearly a growing willingness to offer young people drugs which may have profound effects on how they think and behave. For some children, the benefits conspicuously outweigh any drawbacks. For others, I wonder how far the perceived costs and benefits simply reflect our own shifting values
Baroness Susan Greenfield is professor of pharmacology at Oxford University and director of the Royal Institution of Britain
1 Smoking, drinking and drug use among young people in England 2005, published August 2006 by the NHS Information Centre.