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Researchers
have pinpointed a mechanism in the brains of mice that could explain
why some human mothers become depressed following childbirth. The
discovery could lead to improved treatment for postpartum depression.
Supported in part by the National Institute of Mental Health, of the
National Institutes of Health, the study used genetically engineered
mice lacking a protein critical for adapting to the sex hormone
fluctuations of pregnancy and the postpartum period.
"For the
first time, we may have a highly useful model of postpartum
depression," said NIMH Director Thomas R. Insel, M.D. "The new research
also points to a specific potential new target in the brain for
medications to treat this disorder that affects 15 percent of women
after they give birth."
"After giving birth, female mice
deficient in the suspect protein showed depression-like behaviors and
neglected their newborn pups," explained Istvan Mody, Ph.D., of the
University of California at Los Angeles (UCLA), who led the research.
"Giving a drug that restored the protein's function improved maternal
behavior and reduced pup mortality."
Mody and Jamie Maguire, Ph.D., UCLA, report on their findings in the July 31, 2008 issue of Neuron.
Researchers
had suspected that postpartum depression stemmed from the marked
fluctuations in the reproductive hormones estrogen and progesterone
that accompany pregnancy and childbirth. Yet manipulating the hormones
experimentally triggers depression only in women with a history of the
disorder. The roots of their vulnerability remain a mystery.
Evidence
suggested that the hormones exert their effects on mood through the
brain's major inhibitory chemical messenger system, called GABA, which
dampens neural activity, helping to regulate when a neuron fires.
Mody and Maguire discovered that a GABA receptor component, called the delta
subunit, fluctuated conspicuously during pregnancy and postpartum in
the brains of female mice, hinting that it might have pivotal
behavioral effects. To find out, they used mice lacking the gene for
this subunit and studied them in situations that can elicit responses
similar to human depression and anxiety.
Much like human mothers
suffering from postpartum depression, the genetically altered mouse
mothers were more lethargic and less pleasure-seeking than normal mice.
They also shunned their pups and failed to make proper nests for them.
This
abnormal maternal behavior was reversed and pup survival increased
after the researchers gave the animals a drug called THIP that acts on
the receptor in a way that specifically restores its function in spite
of the reduced number of subunits.
"Improper functioning of the delta
subunit could impair the GABA system's ability to adapt to hormone
fluctuations during the highly vulnerable post partum period,"
explained Maguire. "Targeting this subunit might be a promising
strategy in developing new treatments for postpartum depression."
Reference
Maguire J, Mody I. GABAAR plasticity during pregnancy: relevance to postpartum depression. Neuron. 2008 Jul 31; 59
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Content” located at the bottom of this blog post.
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“Psychiatric Disorders: Postpartum Depression” or type in the keyword
“postpartum depression” into “Google Search” located in the sidebar.
For more books with related
content, click any hyperlinked keyword in the blog or type in the keyword,
“postpartum depression” into “Amazon Search” on the Amazon banner located
in the side bar.
For related articles on
postpartum depression disorders on the Web, click on: “Sphere: Related
Content” located at the bottom of this blog post.
For related books or blog
posts with related content in Dr. Jeff’s and Dr. Tanya’s Blog, go to
“Psychiatric Disorders: Postpartum Depression” or type in the keyword
“postpartum depression” into “Google Search” located in the sidebar.
For more books with related
content, click any hyperlinked keyword in the blog or type in the keyword,
“postpartum depression” into “Amazon Search” on the Amazon banner located
in the side bar.
Many pregnant patients are concerned about the risk of developing postpartum depression. Thus, a commonly asked question is: “How common is postpartum depression?” A new study reported in Medscape, titled “Prevalence of Self-Reported Postpartum Depressive Symptoms -- 17 States, 2004-2005,” issued by the Centers for Disease Control and Prevention (CDC) and published in the Morbidity and Mortality Weekly Report, April 11, 2008, attempts to answer this question. The results of the study showed that self-reported postpartum depressive symptoms (PDS) were surprisingly high. “…During 2004-2005, the prevalence of self-reported PDS in 17 states ranged from 11.7% in Maine to 20.4% in New Mexico.” In addition to determining the overall rate of postpartum depression, the study also pinpointed five major risk factors associated with the development of postpartum depression. “PDS was significantly associated with five possible risk factors in all or nearly all of the 17 states…using tobacco during the last 3 months of pregnancy, physical abuse before or during pregnancy, partner-related stress during pregnancy, traumatic stress during pregnancy, and financial stress during pregnancy.” The results of this study show that postpartum depression is a common affliction and that there are five important risk factors that may greatly increase the chances of developing the disorder.
The Bottom Line: Postpartum depression is a common disorder and five risk factors greatly increase the changes of developing this disorder.
A new study in the Journal of Clinical Psychiatry 2007 Dec; 68:1947 clarifies who is at risk for developing postpartum depression twelve months after delivery. The Danish study measured the incidence of psychiatric disorders in both mothers and the mothers’ partners and the mothers’ first degree relatives during the first year after delivery. The results were surprising. Thirty-four percent of mothers who required inpatient or outpatient treatment during the first twelve months after delivery had a partner or a first degree relative who had a psychiatric disorder. In addition, the highest risk for developing a postpartum depression for a mother was during the first thirty days after delivery. The risk was even higher during the first thirty days for those mothers who also had a first degree relative (particularly with the diagnosis of Bipolar disorder) and a partner who had a psychiatric disorder.
The Bottom Line: The highest risk for developing a postpartum depression for a mother is during the first thirty days after delivery. The risk is even higher during the first thirty days for those mothers who also had a first degree relative (particularly with the diagnosis of Bipolar disorder) and a partner who had a psychiatric disorder.
Sources: Journal of Clinical Psychiatry, See blogposts in: Psychiatric Disorders: Depression
