SIGNIFICANT BOUTS of depression and stress can cause the loss of brain volume – literally making the brain shrink, a US study has found.
Researchers from Yale have identified a ‘genetic switch’ which stops connections being built between synapses in the brain whenever a person is feeling particularly stressed or depressed.
This, over time, results in the loss of brain mass in the prefrontal cortex – the part of the brain responsible for ‘executive function’ such as determining good or bad, decision making and personality expression.
Senior author Ronald Duman said he had “wanted to test the idea that stress causes a loss of brain synapses in humans”.
His team analysed brain tissue from depressed and non-depressed patients, sourced from a brain bank – and found that the brains of people who had suffered from depression had a lower presence of the gene expression that builds links between synapses.
ScienceDaily.com explains that one researcher found that at least five of these genes could be linked to a single transcription factor, or ‘genetic switch’.
Activating this switch in lab rodents, the researchers found that the rodents also began to show depressive behaviour – indicating that depression may trigger a vicious cycle of stunted synaptic growth, which then leads to further depressive episodes.
Duman told ScienceDaily.com:
We show that circuits normally involved in emotion, as well as cognition, are disrupted when this single transcription factor is activated. [...]
He said that the research could be used to develop new techniques for rebuilding synaptic connections – either through medications or therapy – and ultimately lead to more effective methods for improving mental health.