Students who drop out of university suffer ill effects for more than a decade afterwards, according to a study published this week.
Graduates are generally "happier, healthier and safer" than people with lower qualifications, the Institute of Education study found.
Men who drop out from university are more likely to suffer from depression than people without A levels. Women dropouts are more vulnerable to assault from partners than those who leave school without A levels, the study says.
Both sexes are more likely to be unemployed than graduates, with male dropouts more so than the non A-level group.
One in five students drops out of university, according to the most recent performance indicators.
Evidence shows a correlation between lower A-level points and non-completion of degree courses. Dropouts are predicted to rise as more students with lower entry grades begin higher education.
The study assessed the effects of higher education on adult health, vulnerability, parenting, civic engagement and attitudes, after controlling for factors such as family background characteristics and adult life experiences.
It was based on the National Child Development Survey of 12,000 people who were born in March 1958, some 11 per cent of whom attended university in the late 1970s and early 1980s. The Institute of Education study focused on interviews conducted in 1991 when those in the national survey were 33.
John Brynner, who conducted the study for the institute, said: "It is a chicken and egg situation (whether students who drop out become depressed or whether depressed students drop out).
"There is a sense of self-esteem building of higher education and this is probably what we are picking up aged 33. Dropping out must have a damaging effect on self esteem.
"It is interesting that for women we don't have this effect. For women, there is no real impact of dropping out on depression. It may be that women are leaving higher education to form relationships and have a family."
The study also showed that mature graduates were the least depressed group among men and the group least vulnerable to assault among women.
Overall, graduates are more likely to see themselves as being in excellent health, less likely to suffer from depression, have children with fewer educational problems and, if male, are less likely to be the victims of accidents or assaults compared with non-graduates, the study found.
Sir Brian Fender, chief executive of the Higher Education Funding Council for England, which commissioned the research, said: "Clearly, higher education is a profound force for social good and this research shows why plans to widen higher education to all those who can benefit from it are so important."