Makers of popular antidepressants such as Paxil, Zoloft and Effexor have refused to disclose the details of most clinical trials involving depressed children, denying doctors and parents crucial evidence as they weigh fresh fears that such medicines may cause some children to become suicidal.

The companies say the studies are trade secrets. Researchers familiar with the unpublished data said the majority of secret trials showed that children taking the medicines did not get any better than children taking dummy pills.

Although the drug industry practice of suppressing data unfavorable to its products is legal, doctors and advocates say such secrecy distorts the scientific record.

“We need a journal of negative findings,” said Darrel Regier, director of the American Psychiatric Assn.’s division of research, who believes the drugs save children’s lives. “The probability of those negative findings being published is far less than the chances of positive studies — even journals are not interested in negative studies.”

Concerns about the safety of antidepressants among children have been heightened after a December warning by British regulators that the drugs may trigger suicidal thoughts and increase the rate of self-injury. An expert advisory panel of the Food and Drug Administration is scheduled to meet Monday to examine the issue, but the agency’s full U.S. analysis of the data will likely not be completed until summer.

The U.S. psychiatric establishment largely supports the use of antidepressant medicines in children, with many arguing that abandoning the drugs would lead to more suicides in children with depression. However, its critics, including consumer advocates and some psychiatrists, question whether mainstream psychiatry is biased by widespread financial ties to the pharmaceutical industry.

The answer lies hidden in a maze of secret data, conflicting scientific interpretations and a corporate-funded clinical trial system that is not primarily designed to answer questions of public health.

“If the companies wanted to publish negative studies they could, but companies don’t like to publish negative studies,” said Russell Katz, director of the neuropharmacology division at FDA, which has access to all the data. “It’s amusing so many people are making pronouncements about the data — scientists and physicians — … without seeing the data.”

A chicken infected with bird flu stands in its egg-laying cage in the Kaliboto village of Blitar, Indonesia. This farm usually keeps around 5,500 chickens and has lost 3,000 in the past two weeks. The World Health Organization advised southeast Asia nations that mass slaughter of infected poultry was needed to contain a bird flu that has killed 10 humans, but Indonesia has balked at the order.