The finding comes from an analysis of international health surveys, one showing that 23% of 25-to 64-year-olds without a Leaving Cert reported having depression in the past year, compared to just 9% of Irish people with a third-level education.
While depression levels differed depending on education levels in most of the 30 countries where people were surveyed, the gap was by far the widest here.
The Organisation for Economic Co-operation and Development (OECD) found that removing age, gender or earnings factors, Irish people with the lowest education levels were 11% more likely to have suffered depression. The next highest gap was less than 7% in Austria, and the average was under 3%.
The OECD’s Education at a Glance 2017 report, published yesterday, said it is crucial that education systems ensure a smooth school-to-work transition, even for those who perform poorly at school, as they are the ones who are most likely to suffer from mental illness.
The same report shows that the pay gap between third-level graduates and those without a degree is wider here than in most other OECD countries, a fact that could be used to strengthen arguments for student fee increases or introducing a controversial student loans scheme.