Exposure to various common childhood adversities - such as parental psychiatric disorder, parental substance abuse or a death in the family - is associated with a substantially increased risk of suicide in adolescence and young adulthood, finds a study published by The BMJ today.
The results emphasise the need for effective interventions early in life, aiming to alleviate the risk in disadvantaged children, say the authors.
Despite the overall decline in suicide rates in Western countries during the past decades, suicide in young people is increasing and is ranked as one of the leading causes of death in those aged 15-29.
Previous research has shown that exposure to adversity in childhood increases the risk for self harm in adolescence and young adulthood, but whether childhood adversity is associated with an increased risk for death by suicide is less clear.
So a team of researchers based at the Karolinska Institute in Sweden and the University of California, Los Angeles used Sweden's extensive and high quality nationwide registers to investigate associations between childhood adversity and the risk of suicide in late adolescence and young adulthood up to age 24.
The study involved 548,721 individuals born from 1987 to 1991.
Seven indicators of childhood adversity occurring between birth and age 14 were selected: death in family (suicide analysed separately), parental substance abuse, parental psychiatric disorder, parental criminality, parental separation/single parent household, household receiving public assistance and residential instability (two or more changes in place of residence).
Indicators that the researchers were not able to study included abuse and neglect.
A total of 42% of the participants were exposed to at least one indicator of childhood adversity, mainly parental separation/single parent household (29%) and household receiving public assistance (20%).
During follow-up, 431 individuals died by suicide, corresponding to an average suicide rate of 10.6 per 100,000 person years.
Highest suicide rates per 100,000 person years were found among those exposed to suicide in the family (34.9), parental psychiatric disorder (27.8) and substantial parental criminality (26.6).
Except for parental separation/single parent household, all childhood adversity indicators were associated with about twice the suicide risk compared with those without experience of childhood adversity.
The risk was markedly increased in young people exposed to two or more adversities - and the association remained even after adjusting for school performance and childhood psychopathology.
The researchers point out that this is an observational study, so no firm conclusions can be drawn about cause and effect, and they outline some limitations that could have introduced bias.
Nevertheless, they conclude that this study "provides clear evidence that childhood adversities that are common in the general population are associated with an increased risk for suicide in adolescents and young adults."
They add that these results "emphasise the importance of understanding the social mechanisms of suicide and the need for effective interventions early in life aimed at alleviating the suicide risk in disadvantaged children."
And they stress this should be done "in parallel with wider societal efforts to reduce the size of social disadvantage."