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Mind matters
PhD researcher Daniela Espinoza Oyarce . Photo : supplied .
What ’ s different about the brains of depressed and anxious people ?
Daniela Espinoza Oyarce interviewed by Wade Zaglas
A new study led by Australian National University ( ANU ) PhD researcher Daniela Espinoza Oyarce has recently been published in The Journal of Psychiatry and Neuroscience . The study examined the brains of more than 10,000 people to find out the effects of depression and anxiety on brain volume .
Oyarce and her colleagues found that the brains of individuals with depression only lost brain volume , with their hippocampus area - linked to sleep , appetite and movement - having shrunk . Oyarce hypothesises that this could be linked to chronic stress that " creates a toxic environment " in the brain and is harmful to brain cells .
Interestingly , however , the research team discovered that the brains of people with both anxiety and depression had increases in brain volume . While treatments exist for both depression and anxiety , Oyarce believes a more complex understanding of the brain is required , especially for individuals who have been treatmentresistant ( i . e . have not improved with different types of pharmacological and psychological therapies ).
CR : The mind is still such a mystery for scientists in so many ways , but do we know why the brains of people with depression shrink ? And which parts of the brain are they ? DEO : Unfortunately , we don ' t have a definite answer . However , we think that it may be linked to chronic stress because this disrupts the chemistry of the brain and creates a toxic environment that is harmful to brain cells . As brain cells die , the brain shrinks . We found that people who have depression have shrinking in parts of the brain that regulate sleep , appetite and movement , but in particular in an area that regulates memory and learning called the hippocampus .
A curious part of your study , however , found that when an individual suffered both depression and anxiety , a particular part of the brain increased in volume , the amygdala . Can you tell me about its function and whether there is a hypothesis as to why it gets larger when an individual suffers from both these conditions ? The amygdala is linked to the expression of emotions , such as fear and anxiety . So we can see the connection to anxiety as a mental illness . The main hypothesis that we think is driving the larger size is that anxiety leads to other activity in the amygdala . This other activity creates more and more connections between brain cells and more supporting cells are needed to maintain these connections , which in turn may result in the larger size .
You note that depression is the most debilitating disorder worldwide . If that ' s the case , why do you think people still tend to sweep it under the carpet ? Do you think society is improving in this respect ? This is a complex issue and I don ' t have a single or definite answer . There are many reasons why someone would not talk about mental issues or not seek help . For instance , not having someone to trust , finances or not knowing how or where to get access to help . But there is also stigma attached to seeking help because we may be under the impression that mental issues are only in our head . With this research , we showed that in fact it is also in our brains and can have detrimental effects later in life .
I think , however , that we are improving . Initiatives like the R U OK Day and access to Lifeline , Beyond Blue and other organisations are more prominent and help raise awareness about mental illness .
Teachers are more vigilant of their students ' mental health and even some employers are taking the initiative , especially now during the pandemic . Our own perceptions of mental health may take longer to shift but I ' m positive that we will become a more accepting society .
For decades , medications such as antidepressants and antianxiety medications , as well as a host of different therapies , have been used to treat depression and anxiety . But if we are really going to improve people ' s health long term , how important is it that neurologists keep researching the nature and functions of the brain ? Do we need to know more about the biological characteristics ? I believe this is essential . By studying how brain cells work and how they organise into distinct areas with a specialised function , we can better understand how disease affects the way these cells communicate and how disruptions to function can be linked to symptoms .
With this knowledge , we can develop therapies that are tailored to symptoms of depression and to symptoms of depression and anxiety . ■
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