Zyprexa, taken by about 2 million people worldwide last year, is approved to treat schizophrenia and bipolar disorder. Besides causing severe weight gain, it increases blood sugar and cholesterol in many people who take it, all risk factors for heart disease.

In a statement responding to questions for this article Lilly said it had reported the death of Kauffman to federal regulators, as it is legally required to do. The company said it could not comment on the specific causes of his death but noted that the report it submitted to regulators showed that he had "a complicated medical history that may have led to this unfortunate outcome."

"Zyprexa," Lilly's statement said, "is a lifesaving drug and it has helped millions of people worldwide with schizophrenia and bipolar disorder regain control of their lives."

Documents provided to The Times by a lawyer who represents mentally ill patients show that Eli Lilly, which makes Zyprexa, has sought for a decade to play down those side effects — even though its own clinical trials show the drug causes 16 percent of the patients who take Zyprexa to gain more than 66 pounds after a year.

Eli Lilly now faces federal and state investigations about the way it marketed Zyprexa. Last week — after earlier articles in The Times about the Zyprexa documents — Australian drug regulators ordered Lilly to provide more information about what it knew, and when, about Zyprexa's side effects.

Lilly says side effects from Zyprexa must be measured against the potentially devastating consequences of uncontrolled mental illness. But some leading psychiatrists say that because of its physical side effects Zyprexa should be used only by patients who are acutely psychotic and that patients should take other medicines for long-term treatment.

"Lilly always downplayed the side effects," said Dr. S. Nassir Ghaemi, a specialist on bipolar disorder at Emory University in Atlanta. "They've tended to admit weight gain, but in various ways they've minimized its relevance."

Ghaemi said Lilly had also encouraged an overly positive view of its studies on the effectiveness of Zyprexa as a long-term treatment for bipolar disorder. There is more data to support the use of older and far cheaper drugs like lithium, he said.

Last year, Lilly paid $700 million to settle 8,000 lawsuits from people who claimed they developed diabetes or other diseases after taking Zyprexa. Thousands more suits are still pending.

But Beik is not suing Lilly. She simply wants her son's case to be known, she said, because she considers it a cautionary tale about Zyprexa's tendency to cause severe weight gain. "I don't think that price should be paid," she said.

Kauffman's story, like that of many people with severe mental illness, is one of a slow and steady decline.