Genetics and Manic-Depression

The Saturday Evening Post, March 1996 | Go to article overview

Genetics and Manic-Depression


To learn more about the genetics of manic-depression, we turned to John Nurnberger, Jr., M.D., Ph.D., director of the Institute of Psychiatric Research at Indiana University and professor of psychiatry and medical neurobiology at the Indiana University School of Medicine.

Post: Could you explain the evidence that manic-depressive illness is hereditary?

Dr. Nurnberger: Well, we know there are inheritable or genetic factors involved with these disorders. For instance, the disorder is very much more likely to happen in one twin if the other twin has the disorder. You also see the same kind of preponderance in families of people who have the condition, and you see it in adoption studies. If a person is adopted from a family and develops the disorder, and you trace back to the biological family, it's more likely you'll see the illness occurring in the biological family of a person with depression than you will in a biological family of somebody else.

The genetic determination of these disorders is about two thirds. In other words, about two thirds of the variance in whether somebody is likely to get the disorder or not is probably related to genetic factors. This means another one third of the variance is probably environmental. We don't understand very well yet what the specific genetic factors are, nor do we understand what the specific environmental factors are that may cause this in some people.

Post: What studies are you working on now in this area?

Dr. Nurnberger: The studies at the Institute relate to primarily genetic factors that may be involved in predisposing people to develop bipolar or unipolar disorder. The current evidence in the field suggests there may be a mixture of genes causing these disorders. There is evidence for genes on chromosome 18, X, 11, and 21 as well as some evidence for other areas, but those areas are the ones most likely implicated at present. It seems to be a complex pattern of inheritance. The other thing we are looking at is the effect of stress in causing depression. We have been studying animal models to look at the effects of stress.

Post: Are some populations more prone to bipolar disease than others?

Dr. Nurnberger: That's a difficult question to answer, because it's not clear that the same methods of diagnosing these disorders have been used in different populations. There is some evidence that some populations have relatively higher rates of mania. The Amish have been studied quite intensively, and it does appear, in the Amish in Pennsylvania, that the rate of bipolar disorder is about equal to the rate of unipolar disorder, which would mean that mania may be relatively more common in that population. Also in the Mediterranean populations that have been studied, it appears as though the relative incidence of mania is higher. In Scandinavian populations, it appears that the relative incidence of depression is higher. But again, it's somewhat hard to compare different populations unless you're really clear that you're using exactly the same methods of diagnosing.

Post: What is the prevalence of depression?

Dr. Nurnberger: It depends on how you define depression as to how many people are affected. In its milder forms, you may be talking about 40 percent of the population who, at one time or another in their lives, have symptoms of depression. In its severe, incapacitating forms, it's more like seven percent of the population. In manic-depressive illness, which has highs as well as lows, it's more like one percent.

Post: Can you describe these severe, incapacitating cases?

Dr. Nurnberger: An incapacitating depression is a state that lasts for weeks or months and involves sadness, inability to enjoy anything, and changes in sleep and appetite. There may be increased sleep and appetite or decreased sleep and appetite. There may also be increased speed of thought and movement together with agitation, or a person may be slowed down and not able to move or think very quickly. …

The rest of this article is only available to active members of Questia

Sign up now for a free, 1-day trial and receive full access to:

  • Questia's entire collection
  • Automatic bibliography creation
  • More helpful research tools like notes, citations, and highlights
  • Ad-free environment

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items

Items saved from this article

This article has been saved
Highlights (0)
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

Citations (0)
Some of your citations are legacy items.

Any citation created before July 30, 2012 will labeled as a “Cited page.” New citations will be saved as cited passages, pages or articles.

We also added the ability to view new citations from your projects or the book or article where you created them.

Notes (0)
Bookmarks (0)

You have no saved items from this article

Project items include:
  • Saved book/article
  • Highlights
  • Quotes/citations
  • Notes
  • Bookmarks
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited article

Genetics and Manic-Depression
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Full screen

matching results for page

Cited passage

Style
Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

"Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Cited passage

Welcome to the new Questia Reader

The Questia Reader has been updated to provide you with an even better online reading experience.  It is now 100% Responsive, which means you can read our books and articles on any sized device you wish.  All of your favorite tools like notes, highlights, and citations are still here, but the way you select text has been updated to be easier to use, especially on touchscreen devices.  Here's how:

1. Click or tap the first word you want to select.
2. Click or tap the last word you want to select.

OK, got it!

Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.

For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

Already a member? Log in now.