Internal documents which appear to suggest Eli Lilly, manufacturer of Prozac, knew 20 years ago there could be a problem, may be relevant to the first British case concerning the drug, now heading for the courts.

Reginald Payne, 63,a teacher from Wadebridge, Cornwall, suffocated his wife and threw himself off a cliff in March 1996. He had been taking Prozac for just 11 days. His family blames the drug and has issued court proceedings against the manufacturers.

The Eli Lilly papers, which chronicle the company's concerns over the restless state of mind of some patients during clinical trials, were produced during a case in Hawaii, the first of some 200 in the US alleging links between Prozac, violence and suicide, to have come to a verdict.

The case concerned a couple who retired to Hawaii from California in 1989. Finding it hard to adjust to the changes in his life, Bill Forsyth saw a doctor and was prescribed Prozac for a mixed depressive anxiety disorder. At first Mr Forsyth said he felt marvellous, but within two days he was imploring his son and wife to get him into a psychiatric hospital. Soon after he returned home, he stabbed his wife June to death and impaled himself on a kitchen knife.

Evidence of violence

The family's lawyers argued in court that Eli Lilly had known for years that patients on Prozac, which was launched in 1988, could suddenly become akathisic - a strange, restless and agitated state of mind in which they can get compulsions to commit violence on other people and themselves.

The lawyers argued that Eli Lilly should be held responsible for failing to warn doctors that some patients might respond in this way and become a danger to others and themselves. Prozac is still a useful and appropriate drug for some patients, they say, but those who take it must be closely watched for the signs of akathisia in the first couple of weeks after beginning a course.

They cited internal minutes from the Prozac development team in August 1978 which ran: "There have been a fairly large number of reports of adverse reactions... Another depressed patient developed psychosis... Akathisia and restlessness were reported in some patients."

The authorities in Germany, considering Eli Lilly's application for a licence in 1984, were concerned. "During the treatment with the preparation [Prozac], 16 suicide attempts were made, two of these with success. As patients with a risk of suicide were excluded from the studies, it is probable this high proportion can be attributed to an action of the preparation." Prozac now carries a warning in Germany of a risk of suicide. "Therefore for his/her own safety, the patient must be sufficiently observed until the antidepressive effect of Fluctin [Prozac] sets in." It adds that the patient may need an additional sedative in the meantime.

The Hawaii family lost its case, but their counsel, Andy Vickery, said they would be appealing on a number of grounds, one of which was the judge's refusal to allow the jury to be told of the German warning. He said: "I was shocked and disappointed to lose. In my final argument, I told the jury their verdict could save lives."

Warning rejected

Graham Ross, a personal injury lawyer based in Neston, Wirrall, who has a number of cases of alleged Prozac-induced suicide on his books, said he takes issue with Eli Lilly because of its failure to warn of the risks to some, not by any means all, patients. "It is their refusal to accept that this is at all possible in any patient, and their insistence that it would have happened anyway that is dangerous and irresponsible, in my view. All we are asking them to do is be more frank in what they say to the medical profession in the first place."

Eli Lilly's spokesmen in the UK and in company headquarters in Indianapolis insist that the Food and Drug Administration (FDA) which licenses medicines in the US, and the Committee on the Safety of Medicines in the UK, had specifically cleared Prozac of inducing suicide in the early 1990s. "That is more important than an attorney's selective manipulation of data," said a US spokesman. "You have to take a look at the patient population. In people with depression there is probably a 15% suicide rate. There is no evidence that Prozac causes suicide."

But although depression is linked to suicide, the rates are highest among those who have been hospitalised, not among those coping in the community who may be prescribed Prozac by their GP and some of whom are anxious rather than depressed.

According to data presented by David Healy, director of the North Wales Department of Psychological Medicine and author of The Antidepressant Era, at the British Association for Psychopharmacology annual meeting in Harrogate in July, the only figures on rates of suicide among depressed people in the UK taking Prozac are six times higher than the probable suicide rates for community depression in the UK, which, he says, "strongly suggests that Prozac may indeed be inducing suicide."

Easing the pain

 Prozac is the world's most widely used brand-name antidepressant, prescribed to more than 38m people in 100 countries.

 It was the first of a new breed of anti-depressants called SSRIs (selective serotonin reuptake inhibitors) to be licensed. They are marketed as having fewer side-effects than older antidepressant drugs.

 It and the other SSRIs work on the assumption that depression is caused by low levels in the body of the chemical serotonin which promotes brain activity.

 Prozac, also known as fluoxetine, blocks the reabsorption of 5HT or serotonin so that an increased amount can stimulate brain cells.

 Prozac is also used to treat obsessive compulsive disorder and moderate to severe bulimia.