A report by the Economic and Social Research Institute has found young adults are facing significant challenges with their physical and mental health.
The 'Growing Up in Ireland' study has collected information on this group of young people since 1998.
More than 5,000 young people were interviewed aged nine, 13, 17, 18 years and 20 years of age for this latest round of results.
The 20-year-olds have described their lives and well-being in the areas of health, work, home, education, relationships, and leisure time.
The report found over two thirds (69%) were in education or training, and over a quarter (26%) were in either full or part-time employment.
The ability to live at home while studying was a very important factor to a third of young people.
A quarter of the 20-year-olds reported above normal stress scores, with almost a third of women more likely to report it than a fifth of men.
They all reported financial stress was a factor.
One of the reports co-authors, Dr Desmond O’Mahony, said that was a worrying trend for the mental health of the country’s young people.
Friends and family were an important source of emotional support, with most (86%) of them saying they would share their thoughts and feelings with friends, while 69% said they would talk to their mother.
More than half of those questioned (57%) said they were in a romantic relationship.
Nearly one quarter of 20-year-olds (24%) were overweight and a further 13% were obese.
Dr Fergal Lynch, Secretary General of the Department of Children, Equality, Disability, Integration and Youth said the findings are an important resource for policy makers.