Do women have a unique risk of depression?
By Liz Lockhart
Do some women have brain biochemistry that can predispose them to depression? According to a new research study discovery the answer is yes.
The study, undertaken by University of Pittsburgh researchers, found molecular-level changes in the brains of women with major depressive disorder. The researchers believe that the discovery links together two hypotheses of biological mechanisms that lead to the disorder. The supposition is that a genetic deficiency leads to a lower level of a specific brain biochemical factor and a corresponding reduction in function of a key brain neurotransmitter.
The findings are published online in the journal Molecular Psychiatry.
Researchers have known for some time that women are twice as likely as men to develop depression and that they have more severe symptoms and more frequent symptoms. However, only a very small amount of research has ever focused on this, or has been conducted on female animals (not human), noted Etienne Sibille, Ph.D., senior author.
‘It seemed to us that if there were molecular changes in the depressed brain, we might be able to better identify them in samples that come from females,’ he said. ‘Indeed our findings give us a better understanding of the biology of this common and often debilitating psychiatric illness.’
For the purpose of this study, researchers examined post-mortem brain tissue samples of 21 women with depression and 21 similar women who had no history of depression. The investigators found that depressed women had genetic deficits.
Women presented less brain-derived neurotrophic factor (BDNF), and of genes that are typically present in specific subtypes of brain cells, or neurons, that express the neurotransmitter gamma-aminobutyric acid (GABA).
These findings were seen in a particular region of the brain known as the amygdale. This area is involved in sensing and expressing emotion.
Researchers have long suspected that low levels of BDNF play a role in the development of depression, and that there also is a hypothesis that reduced GABA function is a key factor, noted Sibbile.
‘Our work ties these two concepts together because we first show that BDNF is indeed low in depression and second that low BDNF can influence specific GABA cells in a way that reproduces the biological profile we have observed in the depressed brain’ Sibbile concluded.
Source: University of Pittsburgh Schools of the Health Sciences
