Researchers Identify Links Between Depression, Stress

People who are especially sensitive to stress are known to be particularly vulnerable to depression. What is the biological explanation for this link? Although the answer is by no means in, it looks as if at least a few of the culprits—the hippocampus region of the brain, brain-derived neurotrophic factor, and a particular variant of the gene that makes this factor—have been identified.

In the past several years, for instance, various researchers have reported that an abnormally small hippocampus is a risk factor for major depression, not the consequence of it (Psychiatric News, August 16, 2002); that brain-derived neurotrophic factor promotes the growth of neurons in the hippocampus region of the brain; and that a deficiency in brain-derived neurotrophic factor may contribute to depression.

And now, Randolph Nesse, M.D., a professor of psychiatry and a professor of psychology at the University of Michigan, and colleagues have made an intriguing link between being especially vulnerable to stress and possessing a particular variant of the gene that makes brain-derived neurotrophic factor. Their finding, published in the February issue of Neuropsychopharmacology, was based on a study of more than 400 subjects.

True, these subjects were relatives of persons participating in a study of high blood pressure, Peter Roy-Byrne, M.D., a professor and vice chair of psychiatry at the University of Washington, pointed out in the April 9 Journal Watch Psychiatry. The select nature of this cohort—persons at genetic risk of hypertension—may limit generalizing results from the study to the general population. Nonetheless, Roy-Byrne believes, one may very well be able to generalize them, and if that is the case, then they point toward a “potential neurogenetic link” between stress sensitivity and depression vulnerability. ▪