The number of victims of heroin-induced brain damage, who are sometimes left blind, paralysed or incontinent, has increased dramatically in recent years, figures show.

Many are left unable to care for themselves, but they are forgotten statistics, ignored amid the publicity surrounding drug deaths and drug-related crime.

Others make significant recoveries and the signs of their brain damage might be subtle. Occasionally they might encounter memory difficulties, behavior problems or decision-making difficulties.

Some need just a couple of weeks of rehabilitation, the more severely injured more than six months. And others are simply too acutely ill to be sent to rehabilitation programs.

Before the 1990s, heroin-related brain damage was a phenomenon rarely seen by the Melbourne rehabilitation medicine specialists, Dr David Burke and Dr Barry Rawicki.

Now, heroin overdose has replaced injury as the major cause of brain damage requiring treatment at the Royal Talbot Rehabilitation Centre’s acquired brain injury unit in Kew, where Dr Burke is a consultant.

Dr Burke, a rehabilitation specialist for nearly 35 years, said he was saddened and disturbed by the growing toll.

“In the past two years it’s been a new disease process for us, and it seems to be very much on the increase, because particularly in the past six months it’s been very busy,” Dr Burke said. Last year at least 11 patients with brain damage from a heroin overdose were referred to Royal Talbot. In 1997, the unit treated five patients suffering brain damage from a heroin overdose and in 1996, none at all. Two young men are still waiting for a bed in the 12-bed unit.

Last month The Age revealed that up to 10,000 patients were treated in Victorian hospitals each year for drug overdoses. Generally, the victims of heroin-related brain damage are aged between the late teens and early 30s. Most are men, some destined to spend the rest of their days in a nursing home.

Dr Burke said the victims came from all groups in society. Some were long-term drug users, some had a drug habit and psychiatric illness, some were possibly drug peddlers and users and others were probably just experimenting, he said.

Often the drug overdose patients rehabilitating in the brain injury unit at Royal Talbot are isolated people, estranged from families and lacking social supports. But others are simply from middle-class Melbourne.

The role of heroin and other drugs in brain injury is also about to be examined in a Melbourne study. The research, by the director of rehabilitation medicine at the Epworth Hospital, Associate Professor John Olver, and other researchers, will investigate how many people who suffer brain injury from road and other accident trauma had drugs or alcohol in their system.

Professor Olver said it was hoped the research would give doctors a better understanding of how to rehabilitate these patients.