Suicidal Threads: Early Abuse Weaves Its Way into the Brain, with Potentially Tragic Consequences

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When sociologist Mike Tomlinson began combing through the health records of people in Northern Ireland, he wasn't interested in suicide. He was on the hunt for links between poverty and international conflict. But he came across a startling trend. From 1998 to 2008, the rate at which men in their mid-30s to mid-50s were committing suicide rose alarmingly fast, more quickly than the rate for the rest of Northern Ireland's population.

At first, that spike made no sense. A peace agreement reached in 1998 transformed Northern Ireland into a prosperous and tranquil place. Economic indicators had been surprisingly good. Suicide rates in neighboring countries were all gently falling. Nothing seemed to explain why so many of these men were killing themselves.

But Tomlinson found a hint in the men's pasts. They had all grown up in the late 1960s and the 1970s, during some of the worst violence Northern Ireland had ever experienced. Called the Troubles, this warlike period brought religious and political fighting that pitted neighbor against neighbor. Children of the Troubles lived with terrorism, house-to-house searches, curfews and bomb explosions. Trauma early in life had rendered men more vulnerable to taking their own lives later, Tomlinson proposed in July in International Sociology.

"If you were younger then, you carry that through," says Tomlinson, of Queen's University Belfast. This idea, that something that happened long ago could have such a profound effect today, seemed to resonate with others. When he described his idea to a suicide prevention group in Northern Ireland, "they just lit on it, and said it speaks so much to what they were seeing."

Tomlinson does not study the brain, but his work has led him to an idea that's been under close scrutiny by people who do. Neuroscientists and psychologists now believe that childhood trauma, including violence and neglect, sears itself into the brain in ways that can have devastating effects later.

"It's a known fact that individuals with early life adversity are at a higher risk of suicide," says Gustavo Turecki, who directs the McGill Group for Suicide Studies in Montreal. A 2001 study in the Journal of the American Medical Association looking at more than 17,000 Californians found that harmful childhood experiences boost a person's lifetime risk of attempting suicide by two to five times. Other studies reveal that people who experienced adversity during childhood make up anywhere from 10 to 40 percent of people who later display suicidal behavior.

All the evidence suggests that childhood trauma can lead to suicide. Now, Turecki says, scientists have to figure out why.

In the last few years, they have begun to turn up molecular scars from past abuse. Some researchers have discovered chemical tags that change genes' behavior in ways that may contribute to suicide. And new evidence reveals that childhood trauma may throw off-kilter the hardware responsible for the brain's response to stress. For a person struggling with suicidal thoughts, dealing with stress appropriately can be a matter of life or death. As more and more signs of these brain changes turn up, the scientific community is struggling to understand how they affect a person's actions, thoughts and decisions--behaviors that sway a person's likelihood of committing suicide.

"This is something we see in the clinic," Turecki says. "People exposed to traumatic events seem to have a harder time adapting to life."

The immediate goal, researchers say, is to better identify people who are likely to act on suicidal thoughts. But in the future, a deeper understanding of the brain scars left by abuse might point to better treatments for someone battling against suicidal behavior, and perhaps even ways to prevent such tragedy.

Something 'truly biological'

Worldwide, about 1 million people take their own lives each year. …