Consistent depression can cause physical damage to the brain, researchers finally concluded after decades of unconfirmed studies.
A study published in Molecular Psychiatry shows that continual depression shrinks the hippocampus, an area of the brain responsible for forming new memories. This leads to a loss in emotional and behavioral functions.
While hippocampal shrinkage has been linked to depression in previous studies, they’ve never been definitive. The inconsistency came from small sample sizes, varying degrees of depression, and the variance in data collection.
Ian Hickie, from the Brain and Mind Research Institute, calls the latest breakthrough “a new spirit of collaboration”; a worldwide, cross-sectional analysis of brain scans from 9,000 people has irrefutably linked brain damage to depression.
“I think this resolves for good the issue that persistent experiences of depression hurts the brain,” the professor said.
The brain shrinkage was especially noticeable for people who were diagnosed with depression early (before 21 years old), as well as patients with recurrent depression. Hicke noted it was the persistence that was most damaging.
“Those who have only ever had one episode do not have a smaller hippocampus, so it’s not a predisposing factor but a consequence of the illness state.
“It puts the emphasis then on early identification of the more severe persistent or recurrent cases, because they’re the ones who will be most harmed from a brain point of view.”
Scientia Professor & Head of the School of Psychiatry at UNSW Philip Mitchell says the collection of data is “becoming a very powerful way of looking at what’s happening in brain function.”
“This study confirms – in a very large sample – a finding that’s been reported on quite a few occasions. It’s interesting that none of the other subcortical areas of the brain have come up as consistently, so it also confirms that the hippocampus is particularly vulnerable to depression.”
As Hicke explained, it becomes imperative that depression is recognized early before the brain starts degenerating. If caught in its early stages, the effects of depression on the brain are reversible with the right treatments.
“The hippocampus is one of the most important regenerative areas of the brain,” said Hicke.