The number of teenagers reporting severe anxiety has doubled in the past seven years.
Cases among young adults have also risen by more than two thirds.
'My World Survey 2' questioned 19,000 young people and found roughly one in four now suffer from the condition.
The study, which is the largest of its kind in Ireland, also shows around one in five report dealing with severe depression.
My World Survey 2 aims to gain new insight into, and increase understanding of, young people’s mental health and wellbeing from a risk and protective perspective within their social context.
Dr. Joseph Duffy, CEO of Jigsaw, says while young people today are more aware of their mental health, social media is having a big impact:
"That really wasn't a significant feature back in 2011/2012. For some young people the longer they spend online that might impact on their ability to actually form social networks and they might be comparing themselves negatively in terms of body image or in terms of friendship networks"