In its solid form, methylphenidate is a class B drug. In liquid form, it is a class A drug. It mimics the properties of cocaine. It is a psychostimulant. It can have side effects, including gastro-intestinal and liver effects, agitation, dependency and psychotic depression. Teachers and others will know this drug as Ritalin or Equasym.

It is currently prescribed to 603 per 10,000 children in Scotland. Eight years ago, the figure was 69 per 10,000 children. That is a huge increase by any standard we choose to apply. And the figures apply to children between the ages of four and 16. It is worth bearing in mind that these figures represent the prescriptions that we actually know about.

Ritalin is given to many children to improve concentration. Its use has been closely associated with attention deficit hyperactivity disorder (ADHD). It is thought that the use of Ritalin will help control behaviour and improve learning. A Scottish Executive document, The Administration of Medicines in Schools, describes Ritalin as a “stimulant medication”, but makes no mention of possible side-effects. The document does, however, indicate the side-effects of those who “suffer” from ADHD.

The drug has been described in the press as a “zombie” drug and as a “chemical cosh”. The health service bill for Ritalin is somewhere in the region of Pounds 2.2 million, and is set to continue rising. Scotland, it seems, has a particularly high rate of prescription. We need to understand this so that we can do better.

It may be a question of resources. If we had more teachers (especially ones trained in special needs), if we had more auxiliaries in classrooms, if we had more psychiatrists and health workers, we could begin to address the needs of the children who are currently prescribed Ritalin much more effectively. Special needs will always be resource-driven because of the very nature of the needs.

It could be a question about finding options. We must invest the time and effort in discovering what the options are. That is a continuum which begins with understanding how ADHD and its associated symptoms come into being, moving on to understanding much more about the nature of learning and how we can meet the needs of each and every learner.

Too often, the needs of children, generally and specifically, are met in a fragmented way. There is often a huge range of professions involved in the education and development of a child. We talk about joined-up thinking - how about joined-up education and development?

It could be a question of better diagnostics. When there has been an increase in a particular crime, the politicians tell us that it is in part due to better policing and reporting procedures.

It could be a question of environment. We all live in a toxic environment, and one which is becoming more toxic. We do not understand fully what effect this is having on children. The toxicity here is not just the very obvious pollution of the atmosphere. It is also about the food that we take into our bodies. Research has indicated that it can have a direct influence on behaviour patterns and on our ability to learn.

There will be much anecdotal evidence from teachers about the behaviour and concentration span of pupils after the lunch break. Filled with additives, colourants and fizzy drinks, pupils who before lunch could settle to work with concentration and attentiveness can give only scant attention to their learning. School meals have tried to respond with healthier options, but the unhealthy options taste and look much better to children.

Several years ago, in research carried out in Wales, half of a class followed a healthy diet and were given vitamin supplements; the other half followed an unhealthy diet. Academic performance, concentration, attentiveness, attainment and positive behaviour patterns were all significantly higher in the group which followed the healthy option.

What we are faced with then is a complex series of influences, some or all of which (as well as those we do not yet know about) can directly affect behaviour and learning. And our response is to throw more chemicals at the child. That is not acceptable.

There needs to be a screening programme which looks at environment, at diet, at health, at learning to date, in order to provide a plan which is child-centred and child-friendly. It must be a plan which puts the welfare of the child at its centre. We cannot continue to poison significant numbers of our children.

Bob Holmes is former depute rector at Hawick High.