Why do Brains Shrink From Depression?

Depression and chronic stress turn off new gene production in parts of the brain

(RxWiki News) Can major depression and chronic stress actually make the volume of the brain shrink? According to researchers at Yale, the answer is yes.

In a recent study, scientists took tissue samples from the brains of people who had major depression.

Results revealed that an important gene activation for proper emotional and cognitive function was halted by depression and stress.

"Talk to a therapist if you're depressed."

Ronald Duman, PhD, professor of psychiatry, neurobiology and pharmacology, and H.J. Kang, PhD, postdoctoral researcher in the department of psychiatry, at Yale University, led an investigation into what stress and depression do to the brain.

For the study, researchers used special devices to look at brain tissue in depressed and non-depressed patients. A brain bank donated the brains for this scientific research.

Loss of brain volume has been found in previous studies in patients with major depression or chronic stress. Loss of brain volume, for any reason, can cause problems with emotions and awareness.

Tissue samples were taken from the parts of the brain that control emotion and cognitive function.

It appeared that when a person has major depression or chronic stress, the brain has a genetic switch that turns off the formation of certain genes called transcription factors.

The formations of this gene is necessary to form connections between neurons so that areas of the brain can communicate with each other.

The shrinkage in brain volume comes from the lack of formation of new neuron connections.

Emotional and cognitive problems can occur when areas of the brain have trouble communicating with each other.

Dr. Duman said, “We wanted to test the idea that stress causes a loss of brain synapses in humans. We show that circuits normally involved in emotion, as well as cognition, are disrupted when this single transcription factor is activated.”

Discovering the shut off of transcription factors and resulting problems could lay the groundwork for new understandings and approaches to the future of treating depression.

Dr. Duman said, “We hope that by enhancing synaptic connections, either with novel medications or behavioral therapy, we can develop more effective antidepressant therapies.”

Dr. Kang looked further into the transcription factor GATA1 and found that it regulated the formation of at least five different genes.  In a rat experiment, Dr. Kang found that, when GATA1 was activated, the rats showed signs of depression. 

This could mean that GATA1 has to do with both the depression and the loss of communication between neurons. 

This study was published in August in Nature Medicine. Funding for this study was provided by the National Institutes of Health and the Connecticut Department of Mental Health and Addiction Services, no conflicts of interest were found.

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Review Date: 
August 15, 2012