Researchers who looked at the brains of suicide victims said on Sunday their findings have helped support theories that childhood abuse can alter the genes and cause lifelong damage.

They found clear changes in the brains of people who were ab used as children and who committed suicide in comparison to the brains of people who were not abused and who died in accidents or suicide.

This helps explain why childhood abuse, such as sexual abuse or neglect, can cause depression, other mental health effects and suicide, and could some day lead to treatments to help victims overcome their abusive childhoods.

Michael Meaney of McGill University in Canada and colleagues examined the brains of 36 people who died suddenly -- 12 suicide victims who had a known history of abuse, 12 suicide victims with no apparent abuse history, and 12 people who died suddenly in accidents.

The abuse included severe physical abuse, severe neglect and sexual abuse.

They looked for changes in genes associated with a stress pathway called hypothalamic-pituitary-adrenal (HPA) function.

"In humans, childhood abuse alters HPA stress responses and increases the risk of suicide," Meaney's team wrote in their report, published in the journal Nature Neuroscience.

Meaney's team found differences in a specific gene called the neuron-specific glucocorticoid receptor or NR3C1 promoter. Changes in this area have been seen in rats and other animals that suffered from neglect or abuse.

Suicide victims with a history of abuse had lowered activity of this gene, compared to victims of sudden, accidental death with no history of abuse. They found no such differences among suicide victims without a history of childhood abuse.