And medical staff in emergency departments are left to deal with the problem.
"My own view is that drug misuse is very much entrenched now in Irish life and Irish culture and it's really close to being as bad a problem or as entrenched a problem as drinking has been for centuries," he told the Herald.
"When I say drugs, the drugs that I expect to see now would be sleeping tablets. There seems to be an enormous epidemic of sleeping tablets," Dr Luke said.
"They seem to have seriously spread into the population of the 15 to 35-year-old age groups as well as the elderly females that they began with.
"In the 1960s they were known as 'mother's little helpers' and they were always an issue with mothers from the '60s and now grandmothers.
"You get a lot of grandmothers very much addicted to long term sleeping tablets but it's a relatively mild problem compared to the misuse now in the 15 to 35 age group which is associated with a lot of violence," Dr Luke said in an interview.
The irony with sleeping tablets is they often make people do anything but sleep.
"For probably 5 to 10pc of users they do the opposite. They make people very violent," said the Cork-based consultant.
Dr Luke highlighted an observation from Harry Kennedy, the head of the Central Mental Hospital in Dundrum, who said that since they reduced prescriptions of the sedative benzodiazepine in the prison service, the problem with violence and abuse has diminished considerably.
"The problem is that people become very detached from life. They don't make proper moral or logical judgements. They become very impulsive. They become very prone to violence, particularly if they run out of their tablets," Dr Luke said.
"The reality is that tens of thousands of people regularly consume the cocktail of alcohol, cannabis and benzo sleepers and it's that cocktail which is a nightmare," Dr Luke added.
"The behaviour is very antisocial, often very impulsive, often very violent."