A 24-year-old man from Weybridge with paranoid schizophrenia stabbed himself 38 times and bled to death in June 2008, weeks after his anti-psychotic drug was changed, an inquest has heard.

The family of Lawrence Crabb has called for a review of the system, which saw his medication changed days before he died.

The inquest in Woking on Tuesday, April 27, and Wednesday, April 28, was told Mr Crabb, who lived with his parents, was diagnosed with schizophrenia in 2003, but the effects had been "stabilised" with the use of anti-psychotic drug Olanzapine.

However, Mr Crabb became increasingly agitated and anxious when his medication was changed to another anti-psychotic drug, Pipotiazine, which he received for the first and only time by injection on June 19, 2008.

Mr Crabb’s psychiatrist, Dr Marco Procopio, told the inquest he did not believe Olanzapine was improving his patient’s condition.

On the morning of June 29, 2008, Mr Crabb said he believed people were coming to "torture" him.

He took a carving knife from the kitchen before barricading himself in his room, where he cut one of his wrists.

His father Brian managed to take the knife from him, but Mr Crabb then took another from the kitchen and started to slash various parts of his body, the inquest heard.

The inquest was told in the 20 minutes it took the emergency services to arrive Mr Crabb lost enough blood to go into hypovolaemic shock – the inadequate circulation of blood through organs.

He was then taken to St Peter’s Hospital, Chertsey, where he was pronounced dead.

During the inquest Professor David Taylor, a psychiatric pharmacist, told coroner Michael Burgess that National Institute for Health and Clinical Excellence guidelines recommended patients being transferred from one drug to another should not immediately be taken off the first drug.

But Dr Procopio said he had not followed this procedure because of his concern that Mr Crabb’s intake of alcohol, mixed with two anti-psychotic drugs, would cause him to die from cardiac arrest or choking in his sleep.

While giving evidence Dr Procopio admitted he should have provided Mr Crabb and his parents with more supervision, knowing the risks of taking a patient straight off Olanzapine.

Dr Procopio also said he realised Mr Crabb was no longer taking his medication, but decided not to tell his parents for “confidentiality” reasons.

He said: “With the benefit of hindsight I understand how difficult a situation Mr and Mrs Crabb found themselves in.

“I absolutely should have [provided further supervision].”

In an emotional scene before the coroner gave his verdict of death by hypovolemic shock, Brian Crabb approached Dr Procopio and thanked him for his honesty in giving evidence.

A statement by Mr Crabb’s parents said: “We hope changes will be made within the mental health service to ensure what happened to Lawrence cannot happen to anyone else.

“We would like Lawrence to be remembered as he was when he was well – a keen sportsman, a good friend and a loving son and brother.

“He was thoughtful, generous and had a great sense of humour.”