A gifted lawyer whose life went into a "downward spiral" after being misprescribed medication for a minor ailment is in line for millions of pounds compensation from a Midland-based pharmacy chain.

Cathy Horton, described by a judge as a "woman of many accomplishments", suffered paranoia, depression and psychotic episodes after taking steroid tablets eight times the strength of her normal dose.

The 44 year-old, who is also ordained as a priest, ended up in the Priory Hospital as her health deteriorated and her anxiety and paranoia increased, the High Court in London was told.

Mrs Horton, formerly of Selsdon, Surrey, launched a damages claim against a doctor and Coventry-based Lloyds Pharmacy Ltd for compensation for the deterioration in her health and the "enormous disruption to her life" which followed.

Upholding her claim against Lloyds, which denied negligence, the judge Mr Justice Keith said her action against the doctor who provided her with the prescription had been settled. Last night Lloyds said it was disappointed by the judgment and was considering an appeal.

Giving his decision, Mr Justice Keith said: "The claimant, Cathy Horton, is a woman of many accomplishments – lawyer, businesswoman, athlete and priest.

"But things changed dramatically for her in 2001 after she had been misprescribed some medication for a minor ailment.

"Her life went into a downward spiral, from which she claims she is only now emerging.

"The basis of the claim is that Lloyds were negligent in not questioning the prescription and in proceeding to dispense the medication which had been prescribed."

He ruled that when the prescription was dispensed at Lloyds’ Selsdon branch in July 2001, the dispensing pharmacist should have followed the instructions in the branch procedures manual and questioned the correctness of the prescription.

If he had done that, the GP’s mistake would have been discovered, said the judge.

Mrs Horton was born in America and in due course moved to the UK. She was taking steroids to supplement an adrenal deficiency.

By 1999 she and her husband, Andrew, were living in Selsdon where he had been been appointed rector. She was working in London as a lawyer earning 550,000 dollars (about #287,000).

Mrs Horton, who has since returned to live in Cleveland, Ohio, was ordained a priest in 2000 and had her own pulpit at St Leonard’s Church in Chelsham, Surrey.

Mr Justice Keith said that by October 2001 Mrs Horton was becoming increasingly aware that something was not right with her health and when her paranoia and anxiety attacks increased she was admitted to the Priory Hospital.

The judge did not give a ruling on how much her claim was worth, but Mrs Horton is believed to be seeking several million pounds.

The judge also said Lloyds had brought "contribution proceedings" against the doctor, which have now been settled.