Fall in number of drug users seeking first-time help for addiction
There were almost 10,000 cases of drug users seeking help for their addictions in 2015.
Official figures from the Health Research Board (HRB) showed a drop in the number of new cases but an increase in the number of addicts returning from treatment, which it said indicated the "chronic, relapsing nature of addiction".
As new laws passed clearing the way for injecting rooms in Dublin, t he review found changes in the types of drugs being used with a slight fall in treatment for the use of opiates such as heroin which now account for half of all cases.
The HRB said the amount of cases of users being treated for problems associated with benzodiazepines had trebled since 2009.
In 2015 there were 873 cases where users reported sedatives or downers as their main problem drug.
But also that year, benzos, as they are often called, were reported as an additional problem drug in 2,258 cases and it had become the first most common additional drug.
Cannabis was the second most common drug among people treated, the HRB report said, and it was also the most common drug in new cases.
There was also a dramatic increase in problems associated with its use with the number of cases up by 72%, from 1,616 in 2009 to 2,786 in 2015.
The HRB report revealed that almost 10% of cases involved a homeless person.
Dr Suzi Lyons, senior researcher at the HRB, said: "The figures also show a decrease in the proportion of new cases, or people presenting for treatment for the first time.
"However, this means there has been an increase in the proportion of previously treated cases, or people returning for treatment, which is an indicator of the chronic, relapsing nature of addiction."
The figures were released as the government confirmed a one-fifth drop in the number of addiction counsellors working in the Health Service Executive since 2006.
Sinn Fein's Pat Buckley, a spokesman on mental health, said it was the equivalent to having 29 fewer people working with addicts despite a slight increase in staff in the last two years.
"If we continue to remove resources after a devastating decade of cuts to community and social services in deprived areas, we will only see the problem get worse," he said.
Some other key findings in the review included:
:: In the seven years from 2009 to 2015, 61,439 cases of problem drug use were treated, excluding alcohol.
:: In 2015 there were 9,892 cases - 38% were new cases.
:: Also that year, 3,511 cases involved people who left school before 16.
:: There was a drop in the number of new cases who reported ever injecting from 19.7% in 2009 to 14.5% in 2015.
:: Seven out of 10 treatment cases were men.
:: Some 2.9% of the cases treated were Travellers, yet the ethnic group makes up 0.7% of the population.
:: Almost two-thirds of those treated reported polydrug use.
:: Cocaine was the third most common drug reported, while reported problem use of novel psychoactive substances - or so-called head shop drugs - which peaked in 2010 at 2.5% of all cases treated, represented 0.9% of all cases treated in 2015.