LONDON - Children and adolescents should not be given the antidepressant Paxil, British health regulators said yesterday after new research indicated that the drug's risk of suicidal thoughts and self-harm was higher in youngsters.

The drug, which is called Seroxat outside the United States and is made by the British-based GlaxoSmithKline (whose U.S. headquarters are in Philadelphia), is not licensed for use in children or teenagers anywhere in the world. However, some doctors give it to treat depression, based on their own judgment.

The new research, provided to Britain's Medicines and Healthcare products Regulatory Agency by GlaxoSmithKline, does not apply to adults, the regulators said.

Britain's Department of Health said the evidence provided by the drug company, from nine studies based on more than 1,000 youngsters, showed there was an increase in the rate of self-harm and potentially suicidal behavior in those under 18 taking Paxil.

GlaxoSmithKline spokesman David Mawdsley said the rate of a collection of emotional side effects, ranging from mood swings and increased crying, to suicidal thoughts and self-harm, was twice as high in the Paxil group as in those taking a fake pill. A total of 3.2 percent of patients on Paxil had the emotional side effects, compared with 1.5 percent of those taking the dummy pill.

"It has become clear that the benefits of Seroxat in children for the treatment of depressive illness do not outweigh these risks," the government said in a statement. "Young people under 18 years currently taking Seroxat for depression should consult their doctor."

Alasdair Breckenridge, chairman of the regulatory agency, said Seroxat's benefits for depressed adults were well-known.

"It is important that patients who are benefiting from Seroxat should not be alarmed by the announcement and should continue their treatment," he said.

It is estimated that almost 17 million people worldwide have been treated with Paxil.