Four-year study seeks volunteers with history of depression
Which genes play a role in depression? Douglas Levinson, MD, professor of psychiatry and behavioral sciences at the Stanford University School of Medicine, is leading a multicenter study to identify them and is seeking volunteers with the illness.
"Our goal is to identify DNA sequences in specific genes that play a role in predisposing some individuals to developing depression," said Levinson, who recently arrived from the University of Pennsylvania, where he had also conducted research on the genetic basis of depression. "The information could ultimately yield better treatments that target the mechanisms identified by this and similar studies."
Major depressive disorder-which is marked by such symptoms as the inability to enjoy life, changes in sleep and appetite, suicidal thoughts, fatigue and poor concentration-develops in about 10 percent of the population. Women are twice as likely as men to develop the disorder.
Past studies show there is a genetic component to depression. Research on twins suggests that about 50 percent of the predisposition to depression is genetic. But, according to Levinson, researchers' knowledge does not extend much beyond that.
"We don't know the cause-not like we know the causes of TB or heart attack," he said. "We have some ideas, but nothing at the level of proof. We're not able to say, 'If this one gene is altered in the following way, that will decrease someone's risk of developing the disease.'"
In recent years, researchers have turned to members of families with multiple cases of depression to gain insight on the genetics behind this disease. For genetic "linkage" studies, researchers test DNA markers throughout the genome and identify the parts of chromosomes where depression-related genes may exist. In one such study published several years ago, Levinson found that a specific part of chromosome 15 is likely to contain one or more genes involved in depression.
"Research on twins suggests that about 50 percent of the predisposition to depression is genetic.""We are continuing to try to pinpoint the relevant genes and the specific role they play in depression," Levinson said. "And that requires our answering several questions: Which genes are they? How do they work together? And how will that information help us in the future?"
Levinson's study focuses on adults with recurrent cases of depression that start in childhood or early adult life. The researchers chose this focus, Levinson said, because past studies have shown that early-onset, recurrent depression seems to be more genetic than later-onset, single-episode depression.
During the four-year study, researchers at six universities will gather information on personal and family mental health history from 2,000 people with major depressive disorder. They will also use blood samples to conduct DNA studies.
Levinson is recruiting 300 participants for the Stanford portion of the study. Eligible participants will have had depression before the age of 31 and have experienced at least two depressive episodes. They must also have at least one sibling or parent with depression.
Also participating in the study are Columbia University, NYC; Howard University, Washington DC; Johns Hopkins University, Baltimore, MD; University of Iowa, Iowa City IA and Rush University Medical Center, Chicago IL.
People who would like more information or are interested in participating in the study should visit http://depressiongenetics.stanford.edu or call .
The study is sponsored by the National Institutes of Health's National Institute of Mental Health.