The figures, published yesterday by the Health Research Board, also show that 83% of the girls admitted had an eating disorder.
More than two thirds of boys under 18 were admitted with a diagnosis of schizophrenia.
Overall, there was a decrease in psychiatric admissions from 19,619 in 2010 to 18,992 in 2011 — a reduction of 627.
The report’s lead author, Antoinette Daily, said a likely reason for the decline in admissions was the growth in the delivery of mental health services in the community. Over half (54%) of all admissions were for single people and there was an equal proportion of male and female admissions.
Those most likely to be admitted were aged 45 to 54, while the 20 to 24 age group had the highest rate of first admissions.
Depressive disorders accounted for almost one third of admissions, schizophrenia one in five, and mania one in nine. Alcoholic disorders accounted for one in 12.
Involuntary admissions increased from 8% in 2010 to almost 10% last year.
There were 118 deaths in psychiatric units and hospitals in 2011. Almost two thirds of all deaths were male and 75% were aged 65 years and over.
Of 435 admissions for people under 18, 70% were to dedicated child and adolescent in-patient units; 26% to general hospital psychiatric units; 4% to psychiatric hospitals and fewer than 1% to independent/private and private charitable centres. More than half of all child and adolescent admissions were female.
Meanwhile, the national mental health recovery organisation, Grow, has reported a 25% surge in middle-aged men in north Dublin seeking help for mental health issues in the past three years.
Grow area co-ordinator for north Dublin, Louise Cleary, said middle-aged men had been the fastest growing group seeking help since 2009.
Grow is holding free educational talks in Car-negie Court Hotel, Swords, Co Dublin, all this month.
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