The time consuming detective work needed to isolate the cause of your child's hyperactivity might seem daunting compared with the medical solution of simply taking methyphenidate hydrochloride. Before you succumb to the temptation of a simple pill, have a look at some of the warnings published by Ciba, its manufacturer, in the American drugs bible, the Physicians' Desk Reference:

This drug should never be used in children under six."Safety and efficacy of long term use of Ritalin [the brand name for methyphenidate hydrochloride] has never been established. Suppression of growth (ie, in weight gain and/or height) has been reported with the long term use of stimulants in children."

There is some clinical evidence that Ritalin may make children with abnormal brain scan readings more prone to seizures.

Symptoms of visual disturbances have been reported.

Nervousness and insomnia are the most common side effects. Others include anorexia, weight loss, abdominal pain, nausea, heart palpitations, involuntary movements, blood pressure changes, toxic psychosis, lowering of white blood cell count and, rarely, Tourette's Syndrome.

"Chronically abusive use can lead to marked tolerance and psychic dependence with varying degrees of abnormal behaviour. . . psychotic episodes can occur. . . " Withdrawal requires careful supervision, since it can bring on severe depression.