Demand for ADHD services is more than doubled in the past two years.
ADHD Ireland says 125 adults sought its help in 2017, that increased to 274 this year.
The charity says roughly 5% of the population has some form of the condition, which affects attention span and can lead to impulsive and hyper activity.
ADHD Ireland spokesperson, Ken Kilbride, said the lack of public services for people is a huge concern.
"At the moment there aren't any services there," said Mr Kilbride.
"So basically, everybody is faced with getting a private diagnosis.
"To get the medication that can be involved in treatment, you need to go to a psychiatrist and at the moment we only know two psychiatrists in the country who are currently taking new patients.
"So it's also difficult to get a private or public diagnosis here in Ireland at the moment."