The decision came at the end of a second inquest into the death of Orville Blackwood, 31, at the top security hospital in Berkshire.
The second hearing was ordered by a High Court judge after Blackwood's mother, Clara Buckley, campaigned for a judicial review. The first inquest in October 1991 also returned a verdict of accidental death.
During the second hearing at Bracknell, the jury was told that Blackwood - who suffered from schizophrenia and had been sent to Broadmoor in 1987 for attempting to rob a post office using a toy gun - was injected with 150 mg of the drugs Sparine and Modecate after attempting to punch a doctor on 28 August 1991. He died of heart failure.
The West Berkshire coroner, Charles Hoile, said the doctor who injected Blackwood 'acted with propriety and professional rectitude and no legitimate criticism against him can be justified'. He also praised nursing staff for their 'competence and attention to duty'.
After the hearing, Mrs Buckley said: 'I am really disappointed at this verdict because my son has died at the hands of so-called capable staff in Broadmoor and it seems no one has accounted for it. The appalling thing is, this is the third young black man who has died in Broadmoor in the same circumstances and this is accidental death. I can't understand it.
'I would like the staff of Broadmoor to come to discuss this situation with me and really to see what they can do to prevent these deaths in hospitals like Broadmoor. I am going to take this campaign as broad as I can. It is time for us to get together as a community to prevent these unnecessary deaths in secure units and hospitals.'
Mrs Buckley added: 'I want care and counselling to be the priority, not drugging.'
Alan Franey, general manager of Broadmoor, said he was relieved the hospital and staff had been exonerated by the verdict. 'The whole episode was tragic and it is a great sadness to have lost a patient in the circumstances in which Orville died. But we have heard from the expert witnesses . . . that he was cared for in a proper and professional way, by dedicated medical and nursing staff.
'This has been on going now for 18 months and these doctors and nurses had to continue in that time looking after seriously ill patients with the knowledge that others were questioning the way they carried out their professional duties. They have found that extremely difficult to cope with and I commend them for what they have done.'Reuse content