Zyprexa is by far Lilly’s best-selling product, with $4.2 billion in sales in 2005, 30 percent of its overall revenues. About two million people worldwide received it last year. Based in Indianapolis, Lilly is the sixth-largest American drug company.

The issue of off-label marketing is controversial in the drug industry. Nearly every company is under either civil or criminal investigation for alleged efforts to expand the use of its drugs beyond the specific illness or condition for which they are approved.

Lilly faces federal and state investigations over its marketing of Zyprexa. In its annual report for 2005, Lilly said that it faced an investigation by federal prosecutors in Pennsylvania and that the Florida attorney general’s office had subpoenaed the company “seeking production of documents relating to sales of Zyprexa and our marketing and promotional practices with respect to Zyprexa.”

Since Lilly introduced Zyprexa in 1996, about 20 million patients worldwide have received the drug, which helps control the hallucinations and delusions associated with schizophrenia and severe mania. But Zyprexa also causes weight gain in many patients, and the American Diabetes Association found in 2004 that Zyprexa was more likely to cause diabetes than other widely used drugs for schizophrenia.

Lilly says that no link between Zyprexa and diabetes has been proven.

As part of the “Viva Zyprexa” campaign, in packets for its sales representatives, Eli Lilly created the profiles of patients whom it said would be suitable candidates for Zyprexa. Representatives were told to discuss the patient profiles with doctors. One of the patients was a woman in her 20s who showed mild symptoms of schizophrenia, while another was a man in his 40s who appeared to have bipolar disorder.

The third patient was “Martha,” a widow with adult children “who lives independently and has been your patient for some time.” Martha was described as being agitated and having disturbed sleep, but without the symptoms of paranoia or mania that typically marked a person with schizophrenia or bipolar disorder.

Ms. Nobles said that Lilly had actually intended Martha’s profile to represent a patient with schizophrenia. But psychiatrists outside the company said this claim defied credibility, especially given Martha’s age. Instead, she appeared to have mild dementia, they said.