Major Depression, Enlarged Pituitary: Which Is the Chicken?

Enlarged pituitary glands have been found in some adolescents with early-onset major depression, raising the question of what role, if any, the gland plays in their disorder.

The finding about the enlarged pituitary glands comes from Vivek Kusumakar, M.D., an associate professor of psychiatry at Dalhousie University in Halifax, Nova Scotia, and Frank MacMaster, a doctoral candidate in anatomy and neurobiology at the National Research Council in Halifax. Results appeared in the May-June Journal of Psychiatric Research.

Some abnormalities in hormones under the control of the pituitary gland have been noted in individuals with a major depression. For example, a failure to suppress blood levels of the hormone cortisol have been noted in major depression subjects after they were given dexamethasone. And in 1991, Ranga Krishnan, M.D., chair of psychiatry at Duke University, and colleagues found enlarged pituitary glands in acutely depressed adult subjects compared with healthy control subjects. So Kusumakar and MacMaster suspected that they might find enlarged pituitary glands in adolescents with major depressive disorder.

They used high-resolution magnetic resonance imaging (MRI) to measure the volume of the pituitary gland in 17 teens with a major depressive disorder and in 17 gender-matched healthy-control teens. The 34 subjects were, on average, 16.5 years old. A trained rater blind to the diagnosis of each subject conducted the MRI measurements.

The subjects with a major depressive disorder were found to have pituitary glands that were significantly greater in volume— by 25 percent—than were the pituitary glands of the control subjects. And even when the researchers eliminated the three depressed subjects who were on psychotropic medications from their evaluations, they still found that subjects with a major depression had significantly larger pituitary glands than did controls.

“To our knowledge,” Kusumakar and MacMaster said, “this study is the first direct comparison of in vivo pituitary volumes between early-onset, adolescent major depressive disorder patients and age- and sex-matched healthy controls, indicating anatomical abnormalities in the pituitaries of these patients.”

Since this study was published, MacMaster told Psychiatric News, he has conducted another study with David Rosenberg, M.D., of Wayne State University, in 25 teens with a major depressive disorder and 25 healthy control subjects, and this time none of the depressed teens were on medication. Again, MacMaster said, larger pituitary volumes were found in the depressed teens.

The question that still needs to be answered is what the enlarged pituitary glands in depressed youth mean. Do they contribute to the depression? Do they stem from it? And do they lead to abnormal hormone production in the body? For instance, one might expect abnormally high levels of cortisol in the blood to occur if a pituitary gland were abnormally large in volume. Yet while abnormally high levels of cortisol have been noted in adults with major depressive disorder, such high levels appear to be rare in teens with the disorder.

In any event, “the findings are interesting and confirm our earlier reports in adults,” Krishnan told Psychiatric News.

To date, only a few studies have examined the size of the pituitary gland in psychiatric illnesses. Abnormally small pituitary glands have been noted in bulimic patients and in children with obsessive-compulsive disorder, and abnormally large pituitary glands have been reported in subjects with alcohol dependence.

The study was funded by the Nova Scotia Health Research Foundation and the Theodore and Vada Stanley Foundation.

An abstract of the study report, “MRI Study of the Pituitary Gland in Adolescent Depression,” can be accessed online at<www.sciencedirect.com/science/journals> by clicking onJournal of Psychiatric Research. ▪