A report by the Medicines and Healthcare Products Agency in the UK last September said clinical trial data linked an increase in the risk of suicidal thoughts and behaviour with the use of Strattera, regarded by some as a "wonder drug". Of 1,357 patients tested, five children showed suicidal thoughts, while one child attempted suicide. They were all aged between seven and 12 years.

Of 851 children treated with placebos, no suicidal thoughts or behaviours were recorded.

"This particular safety signal is being investigated and available information on the risks and benefits of Strattera evaluated and, if necessary, new guidance will be issued, " said Professor Gordon Duff, chairman of the Committee on Safety of Medicines in the UK.

A spokeswoman for the Irish Medicines Board said that although Strattera has been licenced, it has not yet been marketed in Ireland.

"The issue of suicidal thoughts associated with use off Strattera has been considered in the context of the licencing application for Strattera, " she said. "[This] was authorised via a European assessment procedure and will be reflected in the final product information, when the product is marketed in Ireland."

It is estimated that between 5% and 10% of Irish children suffer from ADHD, a condition in which a child has difficulty controlling some aspects of his or her behaviour. If left untreated, a child is at significant risk of developing learning difficulties and poor self-esteem.

Treatment for ADHD usually involves behaviour therapy and, if required, medical therapy. Strattera, manufactured by Eli Lilly, is the first non-stimulant drug to treat ADHD.

"The key to Strattera is that it is non-stimulant and when it came on stream, it was seen as the shining light of ADHD treatment, said Colman Noctor, clinical nurse manager at Lucena Clinic, Dublin. "The links to suicide can often be tenuous, because who's to say the patient wasn't suicidal from their condition. Having said that, suicide rates are unbelievable in Ireland at the moment and services are overwhelmed. I imagine these links with Strattera could influence parents against it."

Stephanie Mahony of HADD, the Hyperactive and Attention Deficit Disorder Family Support Group, said:

"All medications have side effects and only a minute percentage of Strattera patients have been found to have these suicidal thoughts. If the condition goes untreated, the consequences can be very severe. Medication is always a last resort. . . but if it suits your child, and you monitor them closely, it can work very well."