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A new study by a team of researchers from Yale University claims that major depression and stress can cause loss of brain volume, which contributes to emotional and cognitive impairment.

According to the scientists, the reason behind the same is apparently a single genetic switch which triggers loss of brain connections in humans and depression in animal models. The loss of the brain volume takes place in the prefrontal cortex.

The study has revealed that the genetic switch known as a transcription factor suppresses the expression of various genes that are required for the formation of synaptic connections between brain cells.

"We wanted to test the idea that stress causes a loss of brain synapses in humans," said senior author Ronald Duman, the Elizabeth Mears and House Jameson Professor of Psychiatry and professor of neurobiology and of pharmacology, in the press release. "We show that circuits normally involved in emotion, as well as cognition, are disrupted when this single transcription factor is activated." T

For the study, the research team analyzed the brains of patients who were depressed and those who were not depressed during their life time. The brains were donated from a brain bank.

The findings revealed that brains of depression patients showed lower levels of expression in genes required for the function and structure of brain synapses.

According to lead author H.J. Kang, at least five of these genes could be regulated by a single transcription factor called GATA1. With the activation of GATA1, rodents exhibited depressive-like symptoms. This suggests that the transcription factor plays a significant role in the loss of connections between neurons and also in the symptoms of depression.

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

The findings were reported in the Aug. 12 issue of the journal Nature Medicine.