Pharmaceuticals giant GlaxoSmithKline is facing legal action from hundreds of people hooked on the anti-depressant drug Seroxat.

A firm of solicitors has already gathered a dossier of evidence from more than 850 clients including a Durham man who claimed it would be easier to withdraw from heroin than Seroxat.

Mark Harvey a partner with Hugh James solicitors in Cardiff, said they wanted its manufacturer, Glaxo, to issue tougher warnings about the drug's side effects and carry out research into dependency problems.

"There's a claim that taking the drug can lead to significant bouts of depression and suicidal tendencies, but the greater problem is with withdrawal," he said.

"In many cases, people have complained that they feel worse than they did before, and some have spent eight, nine and ten years trying to come off the drug."

Seroxat is usually prescribed for mild depression, anxiety and phobias and, like Prozac, is one of the class of drugs known as selective serotonin re-uptake inhibitors (SSRI).

But there have been more than 1,200 complaints from doctors under a scheme set up by the medicines control agency (MCA) for reporting drugs' side-effects.

Mr Harvey said new cases were coming in at a rate of about 10 a day. He said people were more concerned about issuing tougher warnings rather than simply seeking compensation.

"We recognise that it does help some people so we're not saying it should come off the market. But doctors should have better information at their finger tips when deciding whether or not to issue appropriate treatment."

There have been similar complaints in America and a US federal court judge has already ordered Glaxo to pull television adverts which state the drug is non habit-forming.

The company, which employs 1,500 people at Barnard Castle, County Durham, maintains that Seroxat is safe and that there is no reliable, scientific evidence that the drug leads to addiction.

A spokesman said: "We have yet to be approached by the firm of solicitors. We conduct extensive clinical trials and monitor them on a regular basis as is the company's policy."