The Neurobiology of Depression – Depression and the Brain
Major Depressive Disorder: it isn’t just “all in your head.”
This paper discusses seven research areas relating to the neurobiology of major depressive disorder (MDD). In other words, it talks about the biological evidence of depression, mental illness. It discusses the strengths and weaknesses of biological theories of depression via evidence and aims to point out some of the reasons our current treatment isn’t as successful as it should be. Hasler’s article talks about the neurobiology of mental illness and how depression treatment effects that neurobiology.
The paper cites 88 other studies and was published in the Journal of World Psychiatry in 2010. It’s pretty educational.
Neurobiology of Depression – Depression Is In the Brain
The neurobiology (biology of the brain) of major depression research areas discussed include:
- Psychosocial stress and stress hormones
- Neurotransmitters such as serotonin, norepinephrine, dopamine, glutamate and gamma-aminobutyric acid (GABA)
- Neurocircuitry (neuroimaging)
- Neurotrophic factors
- Circadian rhythms
(That brain scan for mental illness stuff I mentioned a little while ago is covered in more detail in the article.)
Biological Evidence for Depression Layperson’s Articles Available
I wrote a layperson’s version of the article on Breaking Bipolar at HealthyPlace: Biological Evidence for Depression – Mental Illness exists, part 1 and part 2. I take out the big words and try to explain the crux of central ideas in English rather than scientist. (And if you’re super lazy, there is a table in the article that summarizes the neurobiological theories of depression along with their strengths and weaknesses.)
Here are a couple of notes that didn’t make the Breaking Bipolar article.
Aspirin May Make Antidepressants Work Faster
This very small cited study suggests acetylsalicylic acid (ASA) (also known as aspirin) taken with a selective serotonin reuptake inhibitor (SSRI antidepressant) can make antidepressants work more quickly. This is pre-clinical data so it may end up meaning nothing, but it is interesting. It’s discussed in Stress Hormones and Cytokines section of Hasler’s article.
Protein Involved in Stress Response, Neurogenesis and Depression
(How do Antidepressants Encourage Brain Cell Growth?)
Consistently, studies show parts of untreated depressed brains shrink, but we don’t really know why. We also know antidepressants (and electroconvulsive therapy) increase neurogenesis (making of new brain cells) but again, we aren’t sure why.
Hasler’s article discusses glucocorticoid receptors. It mentions their possible role in depression, specifically, in The Neurotrophic Hypotheses of Depression section it mentions glucocorticoid neurotoxicity as a possible mechanism of brain volume loss seen in depression.
Interestingly enough, scientists have just figured out the glucocorticoid receptors are essential for neurogenesis and they “turn immature stem cells into adult brain cells.” And what’s more, antidepressants activate these glucocorticoid receptors.
Why Care About Biological Evidence of Depression?
The answer to this one is pretty obvious if you read the comments here: people think mental illness, depression, bipolar don’t exist as diseases. People think mental illness isn’t biological. People think there is no evidence of physical mental illness. People say there is no science behind mental illness. People say there is no science behind mental illness treatment.
Well, they’re just wrong.
I recommend you read the whole paper, or read my layperson’s translation. Reading about the real studies, the real people, the real images and the real research behind the biology of mental illness brought me back to reality.
Mental illness exists. Depression exists. It’s not just you. It’s just your brain.