New research has found that childhood adversity, such as parental conflict, death of a close family member or serious injury, before the age of nine was associated with mental health problems in late adolescence.

However, the research also shows that improving the relationship between parents and children could prevent subsequent mental health problems, even in children who have experienced severe adversities. The research also indicated that improving a child's self-esteem and increasing their levels of physical activity can help to reduce the risk of developing mental health problems.

The study, led by researchers from RCSI University of Medicine and Health Sciences, is recently published in Psychological Medicine.

The research team analysed data from over 6,000 children in Ireland who took part in the Growing Up in Ireland study. The results showed that just over a quarter of children had experienced childhood adversity before the age of nine.

At age 17 and 18, almost one in five of the young people were experiencing significant mental health difficulties. 15.2% had developed internalising problems, such as anxiety or depression, and 7.5% had developed externalising problems, such as conduct problems or hyperactivity.

Those who experienced childhood adversity were significantly more likely to report mental health problems in late adolescence.

Parent-child conflict explained 35% of the relationship between childhood adversity and late adolescent externalising problems. The conflict also accounted for 42% of the relationship between childhood adversity and internalising problems.

The child's self-esteem (also called self-concept) explained 27% of the relationship between child adversity and later internalising problems. The child's level of physical activity explained 9% of the relationship between childhood adversity and later internalising problems.

"Children who experience multiple or severe life events are at an increased risk of mental health problems, but not all of those exposed to such events develop such problems. Our research points to some factors that can be useful for off-setting the risk of mental health problems in those who have been exposed to difficult life events," said Dr Colm Healy, the study's lead author and postdoctoral researcher at RCSI University of Medicine and Health Sciences.

The work was funded by the Health Research Board in Ireland and the European Research Council.

"Among children who have experienced adversity, we found that reducing conflict between the parent and child and fostering a warm relationship can protect them from a broad range of later mental health problems," said Professor Mary Cannon, the study's principal investigator and professor of Psychiatric Epidemiology and Youth Mental Health at RCSI.

"We also found that improving a child's self-esteem and encouraging physical activity may also be useful intervention targets for preventing difficulties with mood and anxiety following earlier adversity. On the whole, this is a hopeful story that points towards effective interventions to improve outcomes for children who had experienced difficulties early in life."