With the issue of both "custodial deaths" and widespread drug use becoming a serious political issue, the studies by Professor John Henry of St Mary's Hospital, London, with American scientists, provide a weighty counter to claims that police can pose a risk to people they arrest.
Last year, a record total of 65 people died in police custody in England and Wales. But Professor Henry said that a number of those deaths were certainly people who were long-term users of cocaine - particularly those given to "bingeing" once a week.
He cited the case of Nathan Delahunty, a 29-year-old white businessman who called police to his flat in July last year, saying that people were breaking in through the windows. When the police arrived they found Delahunty alone, half-clothed in the bathroom, sweating profusely and babbling incoherently.
The police decided to take him to a psychiatric hospital for observation, but while in the van his condition worsened. They took him to a casualty ward where he died of respiratory failure.
In January an inquest decided by majority verdict that Delahunty died of "cocaine intoxication". But some jury members, unhappy with the police evidence, called for the case to be reopened, and it has been cited by police opponents as an instance of brutality during arrests.
The condition that affected Delahunty is described in New Scientist magazine today by Steven Karch, an American forensic toxicologist, as Excited Delirium (ED). It appears to be the result of a defect in the body chemistry which deals with dopamine, a "pleasure chemical" released inside the brain whenever cocaine is taken. People who suffer ED seem unable to remove an excess of this chemical. But it only happens to long-term users,said Professor Henry.
The only way to prevent death is to lower the body temperature rapidly, by packing the person in ice.
Detecting ED requires that brain tissue samples are removed within 12 hours of death, otherwise the chemical clues break down, said Dr Karch. However, many autopsies are delayed for more than a day and brain tissues are not always analysed.
"The fact is that in cases like these it is almost certain that if these people were not restrained, they would still die," said Professor Henry. "They still need to be restrained, though, for their own and for public safety. The problem is that the police then get criminalised. Civil rights groups and racial interest groups jump on them, when they should be trying to establish facts."
At a meeting of the Royal Society of Medicine in London this week, Dr Karch claimed that the documented cases of ED are just the tip of the iceberg. Professor Henry said: "We certainly see cases here.The result of ED is that sufferers will often strip off their clothes and go outside to try to cool down. If they see their reflection in a shop window they will try to attack it. As you can expect, a paranoid, wild, incoherent, nude figure on the street is going to attract the attention of the police."Reuse content