Ghostwriting has become widespread in such areas of medicine as cardiology and psychiatry, where drugs play a major role in treatment. Senior doctors, inevitably very busy, have become willing to "author" papers written for them by ghostwriters paid by drug companies.

Originally, ghostwriting was confined to medical journal supplements sponsored by the industry, but it can now be found in all the major journals in relevant fields. In some cases, it is alleged, the scientists named as authors will not have seen the raw data they are writing about - just tables compiled by company employees.

The doctors, who may also give a talk based on the paper to an audience of other doctors at a drug company-sponsored symposium, receive substantial sums of money. Fuller Torrey, executive director of the Stanley Foundation Research Programmes in Bethesda, Maryland, found in a survey that British psychiatrists were being paid around $2,000 (£1,400) a time for symposium talks, plus airfares and hotel accommodation, while Americans got about $3,000. Some payments ran as high as $5,000 or $10,000.

"Some of us believe that the present system is approaching a high-class form of professional prostitution," he said.

Robin Murray, head of the division of psychological medicine at the Institute of Psychiatry in London, is one of those who has become increasingly concerned. "It is clear that we have a situation where, when an audience is listening to a well-known British psychiatrist, you recognise the stage where the audience is uncertain as to whether the psychiatrist really believes this or is saying it because they them selves or their department is getting some financial reward," he said.

"I can think of a well-known British psychiatrist I met and I said, 'How are you?' He said, 'What day is it? I'm just working out what drug I'm supporting today.'"

Marcia Angell, former editor of the New England Journal of Medicine, wrote a year ago that when she ran a paper on antidepressant drug treatment, the authors' financial ties to the manufacturers - which the journal requires all contributors to declare - were so extensive that she had to run them on the website. She decided to commission an editorial about it and spoke to research psychiatrists, but "we found very few who did not have financial ties to drug companies that make antidepressants."

She wrote: "Researchers serve as consultants to companies whose products they are studying, join advisory boards and speakers' bureaus, enter into patent and royalty arrangements, agree to be the listed authors of articles ghostwritten by interested companies, promote drugs and devices at company-sponsored symposiums, and allow themselves to be plied with expensive gifts and trips to luxurious settings. Many also have equity interest in the companies."

In September her journal joined the Lancet and 11 others in denouncing the drug companies for imposing restrictions on the data to which scientists are given access in the clinical trials they fund. Some of the journals propose to demand a signed declaration that the papers scientists submit are their own.

The success of Prozac, the antidepressant which became a cult "happy" drug in the 1990s, substantially raised the stakes in psychiatry. Its promotion coincided with the decline of state funding for research, leaving scientists in all areas of medicine dependent on pharmaceutical companies to fund or commission their work. That in turn gave the industry unprecedented control over data and ended with research papers increasingly being drafted by company employees or commercial agencies.

The responsibility of scientists for the content of their papers takes on serious significance in the context of court cases in the US, where relatives of people who killed themselves and murdered others while on SSRIs (selective serotonin reuptake inhibitors) - the class of drug to which Prozac belongs - claimed the drugs were responsible. According to David Healy, a north Wales-based psychopharmacologist who has given evidence for the families, the companies have relied on articles apparently authored by scientists who may in fact have not seen the raw data.

Dr Healy, who had unprecedented access to the data that the companies keep in their archives, said: "It may well be that 50% of the articles on drugs in the major journals across all areas of medicine are not written in a way that the average person in the street expects them to be authored."

He cites the case brought last year against the former SmithKline Beecham (now GlaxoSmithKline) by relatives of Donald Schell. The court found that the company's best-selling antidepressant, an SSRI called Seroxat, had caused Schell to murder his wife, daughter and granddaughter and commit suicide.

The company's defence was based on scientific papers which analysed the results of trials comparing Seroxat with a placebo and found there was no increased risk of suicide for depressed people on Seroxat. But the raw data probably does not support that, argues Dr Healy. Some of the placebo suicides took place while patients were withdrawing from an older drug. When the figures are readjusted without these, he says, they show there is substantially increased risk of suicide on Seroxat.

This raises the question of whether the eminent scientists whose names were on the papers ever saw the raw data from the trials - or saw only tables compiled by company employees, he says. David Dunner, a professor at the University of Washington, who co-authored one of the papers in 1995, admits he did not see the raw data. "I don't know who saw it. I did not," he said. "My role in the paper was that the data were presented to us and we analysed it and wrote it up and wrote references."

His co-author Stuart Montgomery, then of St Mary's hospital medical school in London, declined to answer calls and emails from the Guardian. The third name on the paper is that of Geoff Dunbar, a company employee.