European research has found that depression, anger, anxiety attacks and suicidal feelings are more common in relatives of those disabled by road accidents than the victims themselves.
It was just one of the findings presented at a conference on the human impact of road collisions in Dublin today.
The conference was also told about a study of victims in the US which found that two years after a collision 40% of victims had Post Traumatic Stress Disorder and 90% had developed driving difficulties.
The conference also heard from Ann Moran, whose daughter Regina was killed in a road crash in 2002, just days before her 20th birthday.
Ms Moran said that road accidents tear families apart and that has an ongoing effect on those who are left behind.
Figures were also presented by the Health Service Executive, which show that between 2005 and 2009 the number of people hospitalised as a result of road collisions fell slightly.
But the severity of their injuries and the profile of the victims remained the same. Most were in their teens and early 20s and they were predominately male.