Half of the population do not have access to a mental health rehabilitation team.
A 13-year-old government mental health policy recommended that 48 teams are needed across the country.
Today there are 23, with none in Donegal, Wicklow or North Tipperary.
CEO of the Mental Health Commission John Farrelly says even where there are services, they are not well staffed.
He said: "In Galway there are two teams, but it's a very large area in terms of both urban and rural but the teams are poorly staffed.
"In Mayo, the team only covers the Castlebar area, leaving a large part of the county without a rehabilitation service."