MONDAY, Jan. 14, 2002 (HealthDayNews) -- Suffering a head injury as a young adult could leave you more vulnerable to bouts with minor and major depression in the years -- even decades -- that follow, says new research.
The study of World War II veterans found that the risk of depression stayed higher for half a century after the injury, and was highest in those who suffered the most severe head traumas.
One expert says the findings, which appear in the January issue of the Archives of General Psychiatry, challenge existing ideas about how long depressive illness can persist after a head injury.
More than 1.2 million Americans suffer head injuries every year, 50,000 of which are fatal. It is estimated that 5.3 million Americans live with a head injury-related disability.
The latest study involved 520 male U.S Navy or U.S. Marine Corps veterans who were hospitalized with a head injury while in service in 1944 and 1945. Using military medical records, researchers from Duke University, the National Institute on Aging and Johns Hopkins University matched the group to 1,198 similar vets who were hospitalized for injuries that didn't involve the head.
The men were roughly 21 years old when they sustained the injuries. Only 7 percent were the result of fighting and 17 percent resulted from blast concussions. Twenty six percent occurred during motor vehicle crashes, 19 percent resulted from a fall, 12 percent were sports-related and another 19 percent were listed as miscellaneous.
Lead investigator Dr. Tracey Holsinger says that, initially, she was surprised to discover how common depression was among the veterans. Major depression was diagnosed in 8.5 percent of the non-head injury group and in 11.2 percent of the head injury group.
But the surprises didn't stop there. The group of veterans who didn't suffer a head injury had a lifetime risk of depression of 13.4 percent, while those who suffered a head injury while on active duty had an 18.5 per cent risk. The risk increased in the men who had suffered a more severe form of head injury.
"The fact that the control group also were veterans from World War II certainly suggests that we're seeing effects that were as a result of the head injury," says Holsinger, a psychiatrist at the Durham Veterans' Affairs Medical Center in Durham, N.C. "We don't think it's just the post traumatic stress, although we certainly recognize what a tremendous impact that can have on their future function."
Dr. Robert Robinson, the head of psychiatry at the University of Iowa College of Medicine in Iowa City, says that there have been relatively few studies of what happens to people after they have a head injury.
The general assumption, he says, is that when someone suffers such an injury, he or she may become depressed, but that the depression will improve when the injury resolves or the person adjusts to the disability.
However, this study showed over a very extended period of time that, after a head injury, people are more likely to suffer from depressive disorders that recur periodically throughout life.
"We were unaware of how long depressive disorders can continue after a head injury," says Robinson.
Exactly how a head injury might be linked to lifelong risk of depression is not as clear, Holsinger says. Robinson's own studies have found an increased likelihood of depression if a traumatic injury or stroke affected one of two areas of the brain called the left frontal cortex or the left basal ganglia.
"If those areas were injured, there was a significantly increased likelihood of developing depression," Robinson says. "One of the ideas that we have proposed is that injury to these strategic areas of the brain trigger
[depression]
by interfering with the normal function of a series of circuits within the brain," he says.
Robinson says that the next step will involve searching for ways to treat this kind of depression, and Holsinger says that doctors may want to monitor patients for long-term depressive symptoms after a head injury.
What To Do
Traumatic Brain Injury Survival Guide, an online book, has a section on depression.
To find out more about head injury in general, check out the National Institute of Neurological Disorders and Stroke, or the Centre for Applied Health Research.
