ritish drug regulators warned yesterday that GlaxoSmithKline's popular antidepressant Paxil causes depressed children to become more suicidal and should not be prescribed for them.

That conclusion came from the combined results of nine studies on Paxil, known as Seroxat in Britain, that the company recently submitted to British regulators.

"It has become clear that the benefits of Seroxat in children for the treatment of depressive illness do not outweigh these risks," the statement from the British government's Medicines and Healthcare Products Regulatory Agency said. "The implications of the new pediatric data on the safety of paroxetine (Paxil) in the adult population remains under close review."

Alan Metz, vice president for clinical development at Glaxo, said the company was not warning American doctors against using the drug for depressed children. He noted that Paxil was not approved in the United States for treating children but that many doctors prescribed the drug for children anyway.

"It's difficult for me sitting here to tell doctors what they should do with their patients," Dr. Metz said.

Glaxo, the British drug maker, has applied for permission from the Food and Drug Administration in the United States to sell Paxil to children who suffer from obsessive compulsive disorder. That application is pending. Paxil has become increasingly controversial in Britain.

The British drug agency recently required Glaxo to remove a statement on its patient label saying that the drug was not addictive.

Patients who stop taking Paxil suddenly often experience dizziness, abnormal dreams, headaches and nervousness. In Britain, these are called "withdrawal symptoms" and in the United States they are called "discontinuation symptoms," Dr. Metz said.

Paxil is part of a class of drugs that includes Prozac and Zoloft. For years, lawsuits have contended that the drugs tend to increase violence and suicidal thoughts in vulnerable populations, but the makers of the pills have long denied this. Two years ago, a Wyoming jury awarded $6.4 million to the family of a patient taking the pill who killed his wife, daughter and granddaughter.

According to the studies, patients taking Paxil were 1.5 to 3.2 times more likely to have suicidal thoughts or episodes of self-harm compared with those taking a placebo.

The rate of suicidal behavior among those taking Paxil was lower than the normal rate of such behavior among depressed children who got no treatment at all, Dr. Metz said. This is true because treatment — even with dummy pills — can be highly effective against depression.

None of the children in the studies succeeded in committing suicide.

Paxil is GlaxoSmithKline's largest-selling drug. The company is in the midst of a legal fight to retain its exclusive hold over Paxil's selling rights in the United States.