19-year-old college student who had shown no outward signs of depression killed herself over the weekend at an Eli Lilly & Company laboratory in Indianapolis where she had been participating in a company drug trial for an experimental antidepressant.

The student, Traci Johnson, was one of 25 healthy patients at an Eli Lilly clinic who were being given larger than therapeutic doses of duloxetine, which will be known as Cymbalta if it is introduced as an antidepressant. Four days before her death, Ms. Johnson was taken off Cymbalta and given a placebo.

While Eli Lilly asserted that it had properly screened Ms. Johnson before the study started to ensure that she was healthy and had no mental problems, her death is being used by critics of a popular class of antidepressants to bolster their case that the widely used drugs carry the risk of suicidal tendencies for a small number of people, particularly young people.

Four other patients who were given the drug during earlier trials also committed suicide, the company said. The drug is being tested not only as an antidepressant but also as a possible treatment for stress urinary incontinence.

Ms. Johnson's death came less than a week after a federal advisory panel concluded that the Food and Drug Administration should issue stronger warnings to doctors that this class of antidepressants may be linked to suicide and violent behavior in children and teenagers.

A review board has told Eli Lilly to stop entering new patients into the trial, and to have all the current participants evaluated by an independent psychiatrist.

Robert Smith, a Lilly spokesman, said the company did not believe that duloxetine, the drug's generic name, caused the suicide.

"This drug has been studied in 9,000 patients, in depressed and nondepressed healthy people, and we have not been able to discern any signal between duloxetine and suicide or suicidal ideation," Mr. Smith said.

Ms. Johnson had not shown signs of depression, distress or mood swings throughout about a month in the trial, said Dr. Alan Breier, Lilly's chief medical officer.

Patients who abruptly stop therapy with some antidepressants often experience withdrawal symptoms that can include severe agitation, unusual dreams and night sweats. This is especially true of antidepressants like Paxil, made by GlaxoSmithKline, that leave the bloodstream quickly. Cymbalta also leaves the blood stream quickly.

Dr. Breier said Ms. Johnson did not appear to be suffering any withdrawal symptoms. He said the company might never be able to answer why Ms. Johnson killed herself.

"Most people who commit suicide in the general population leave people asking these kinds of questions," Dr. Breier said. "And just because this happens while someone is taking a drug doesn't mean the drug caused it."

Ms. Johnson did not leave a suicide note. She hanged herself in a shower stall Saturday night in the bathroom of Lilly's dormlike laboratory on the top two floors of the Indiana University Medical Center.

She had been attending nearby Indiana Bible College but left school to participate in the study because it paid $150 a day plus meals.

Whether antidepressants cause some people to commit suicide was an issue that flared briefly in the early 1990's but had been largely dismissed by mainstream researchers until last summer. That is when GlaxoSmithKline warned that a series of studies had found that children and teenagers given Paxil were more likely to attempt or think about suicide than those given a placebo.

Wyeth soon followed with a warning suggesting that its antidepressant, Effexor, should not be given to children. British and American drug regulators set to work studying the problem. The British soon concluded that most antidepressants in this class should not be used in children and teenagers since they have not proved effective in that population and could be linked to suicide.

The F.D.A. continues to study the issue, said Susan Cruzan, an agency spokeswoman. The agency is aware of Ms. Johnson's death and will evaluate its implications once the agency receives all of the needed information about it, Ms. Cruzan said.

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