U.S. regulators should publicize concerns about psychiatric problems in some children who took certain attention-deficit drugs, even though it’s not clear if the medicines caused the behavior, several members of an advisory panel said on Thursday.

Many on the panel of outside experts agreed with Food and Drug Administration officials who said it was premature to update warnings on the drugs, which include Johnson & Johnson’s Concerta and Novartis AG’s Ritalin and its generic competitors.

Still, the FDA should not wait to alert parents and physicians until it reaches a firm conclusion about the potential for suicidal behavior, aggression and other problems, several panelists said. Questions about the methylphenidate stimulants already have received media attention, and the uncertainty needs to be fully explained, they said.

“Empower parents to have enough information to truly monitor their children,” said panel member Deborah Dokken.

Concern about potential psychiatric side effects arose from a routine review of Concerta mandated by law for drugs approved for children.

The FDA received 36 reports over a one-year period of children taking Concerta who experienced aggression, agitation, abnormal behavior, anxiety, depression, visual hallucinations or suicidal thoughts or actions. Sixteen other reports listed Ritalin and other methylphenidates.

Those behaviors are not unexpected in patients who take stimulants, and many disappeared when drug treatment stopped, FDA officials stressed.

“We are not seeing anything we consider particularly new, but we want to be able to communicate it better,” said Dr. Paul Andreason of the FDA’s division of neuropharmacologic drug products.

The treatments for attention deficit hyperactivity disorder (ADHD) already come with warnings about hallucinations, abnormal thinking and other mental problems.

Regulators asked the panel of outside experts for advice because they said they did not want to scare parents away from effective treatments, or prompt switches to other ADHD drugs that could carry the same risk. A review of amphetamines and Eli Lilly & Co.‘s ADHD drug Strattera is due to be completed in early 2006.

“We are struggling with not wanting to appear we are not telling something and trying to get these adverse events completely evaluated so we can come out and say they are all the same or they aren’t,” said Dr. Dianne Murphy, director of the FDA’s office of pediatric therapeutics.

About half of all methylphenidate prescriptions over the past three years were for Concerta. In 2004, more than 6 million Concerta prescriptions were dispensed for patients age 1 to 16, the FDA estimated.

Both Johnson & Johnson and Novartis said they would work with the FDA as it reviewed the safety of the drugs.