Its report shows the number of cases dropped from 8,876 in 2011 to 7,350 in 2017.
However, the number of new cases classified as "alcohol dependent", which would involve withdrawal symptoms, increased from 50% of new cases in 2011 to 68% in 2017.
"This means that more people are presenting when the problem is already severe which makes treatment more complex and recovery more difficult," according to Dr Suzi Lyons of the HRB.
Nearly one in five cases had a problem with more than one drug. Cannabis is the most common additional drug used although the number of cases has dropped by 15%.
Source: John Kilraine, RTE, 20th March 2019