Young people, single people and people with depression continue to dominate admissions for psychiatric care, according to the Health Research Board (HRB).
The overall number of admissions continues to fall and there were an equal proportion of male and female admissions last year.
Young people between 20-24 years of age had the highest rate of all admissions last year, according to the HRB's report on the Activities of Irish Psychiatric Units and Hospitals 2016.
Almost six in ten admissions were single people and depression remains the most common diagnosis.
The number of admissions last year was 17,290 compared with 17,860 for the previous year.
Depression, schizophrenia, mania and alcoholic disorders were the main diagnosis for admissions.
The report shows there were 151 deaths in Irish psychiatric units and hospitals.
