A man who died after being restrained by eight police officers was suffering from a drug-induced delirium, an inquest was told on Wednesday.
By Cindi John
BBC News Online community affairs reporter
Roger Sylvester was being treated for a manic illness
Psychiatrist James Griffiths-Edwards who carried out an assessment of Roger Sylvester's case for the Metropolitan Police said he had no doubt cannabis had played a part in Mr Sylvester's behaviour.
Tests done on Mr Sylvester after he was admitted to hospital showed he had cannabis in his system, Professor Griffiths-Edwards told the hearing in St Pancras, London.
Professor Griffiths-Edwards said Mr Sylvester had been "out of contact with reality" and in a "very abnormal, confused mental state" on the night he was found naked and banging on his front door in Tottenham, north London.
He said Mr Sylvester had apparently switched very quickly from "being neighbourly" to the state in which he was found by police officers in January 1999.
"There are quite a few drugs that could do that. Cannabis is certainly one of them," he said.
The effect of cannabis in a person who had a tendency to mental disturbance could not be predicted and Roger Sylvester might have been "caught out" by the strength of the drug, Professor Griffiths-Edwards added.
But he said he did not think the cannabis had brought on a recurrence of Mr Sylvester's manic illness for which had been receiving treatment and would not have led to his death.
The psychiatrist refused to be drawn on a suggestion by David Bromley-Martin, representing the police officers involved in the case, that Roger Sylvester had been suffering from "Excited Delirium".
But he admitted that in his assessment of Roger Sylvester's case he had mentioned the condition as a possibility and noted that it could trigger heart attacks.
Earlier the hearing had heard from nurse Ben Bersabel who had been on duty the night Mr Sylvester was brought into St Anne's hospital in Tottenham.
He had prepared the room where Mr Sylvester was taken but did not go into the room while the police officers were with him, Mr Bersabel said.
But he said he had been able to see into the room and had noticed Mr Sylvester was being held down on his front.
Mr Bersabel also said he had heard the restrained man calling out for a doctor.
However, that was challenged by the counsel representing the Metropolitan Police Commissioner, Ron Thwaites.
Mr Thwaites, who accused the nurse of being an unreliable witness, said the officers had restrained Mr Sylvester on his side and were the ones who called for a doctor.
The hearing continues.