(These are all of the posts we have on this topic)
1st Post on Stress and Depression Why the Current Theory Fails So Often
2nd Post on Stress and Depression Cortisol
3rd Post on Stress and Depression Pregnenolone
5th Post on Stress and Depression BDNF
6th Post on Stress and Depression: The Cholesterol/Dopamine Connection
7th Post on Stress and Depression: Increasing levels of Brain Derived Neurotrophic Factor (BDNF)
6th Post on Stress and Depression: The Cholesterol/Dopamine Connection
7th Post on Stress and Depression: Increasing levels of Brain Derived Neurotrophic Factor (BDNF)
Hello again,
This blog post is the second in a series of posts that we
will be doing on Depression & Stress.
In the previous entry (click here to see it), we discussed the fact that the current model for
the treatment of depression revolves around one central theme. That theme is called the biogenic amine
hypothesis. This theory views the cause
of depression as a lack of key neurotransmitters (nor-epinephrine, serotonin
& dopamine). The drugs currently
being used to treat depression only focus on increasing these chemicals in the
body, theoretically adding gas to a depressed person’s fuel tank.
This theory appears to be helpful in some people, but not
all, in fact not even half. That is the
purpose of this series of posts we are doing on depression, to look into other
theories than just the standby concept.
Depression is clearly a physical problem. The lack of motivation, aches and pains, and
increased general disease risks, make it clear that depression has roots deeper
than just the emotions alone. Further
these risks relate to an extended period of time. This means that there must be long-term
factors that pre-dispose people to depression (no, we are not talking about inheriting
depression from your parents).
A major factor predisposing people to depression is
stress. Stress impacts the body through
something
The take way from this science is this: once your pituitary
gland is stimulated to release CRH it starts a chain reaction of events that
lead to increased stress hormone levels in the form of cortisol.
So … that’s it! Crush
cortisol and we’re cool calm and collected … right?! Not so fast.
Cortisol is vital to the human body.
Without it, you’ll die. But, it
should be available in short term and/or low grade doses, not the amounts that
stimulate a fight or flight response.
You need to moderate it.
The problem with chronic overstimulation of cortisol
production is that it travels back into brain.
The brain is very receptive to cortisol.
It makes sense, since this hormone is designed to save us from hungry
bears. However, the calm state of
happiness that we all seek doesn’t fit well with running for your life. In fact, cortisol alters levels of serotonin
dopamine and nor-epinephrine (please see our first post about these happy
hormones). This is a cornerstone of the
current thinking regarding what causes depression. But the root of the problem is not a lack of
hormone; that is just a symptom. The
REAL problem is the suppression of happy hormone production caused by stress.
 |
| This is your hippocampus on stress and full of holes |
How can cortisol be destructive? A seminal study done by Robert Sapolsky back
in 1983 found that stress hormones cause brain damage. What he did to discover
this was take rats and plant a placebo or a slow release form of cortisol in
different sections of their brains. The
area of the brain that he was studying was the hippocampus. The hippocampus has two functions that are
vital to our discussion here: management of stress hormone levels and
establishment of long-term memories.
Guess what? The implanted stress
hormones killed off a massive amount of cells in the brain in comparison to the
placebo. What this tells us is that
prolonged exposure to high levels of stress will kill your neurons and brain
tissue. New evidence has emerged that
supports this idea in humans. The
average hippocampus of depressed people has been shown to be smaller than
undepressed people by about 15%. It
gives you something to think about regarding the loss of memory during
traumatic events; it also shows how the poor regulation of stress can lead to
brain dysfunction. They also feed each
other … it’s a slippery slope in a lot of ways … if you lose hippocampal cells
the lining on breaks go. Once the breaks
go on your hippocampus, you can’t control the flood of stress hormones. These stress hormones further damage your
hippocampus and the cycle continues.
This lends some scientific support to the idea that
depression leads to other health problems.
It’s long been known that excessive stress can lead to ill health. Now you can see that depression is just the
end stage of excessive stress hormone production. The good news is that if you start taking
steps to treat your depression, you can stop the wave of problems that come
with depression.
In 2003, Yvette Sheline published a paper studying the function
of the hippocampus in untreated people with depression. Take a look at the chart for people with untreated
depression. But if you treat depression,
Sheline found that it protected the hippocampus. This is very reassuring. If you treat depression, it saves your
brain. This means that treating
depression may be neuro-protective. It
also means that toughing depression out and just living with it may be damaging
your nervous system, and not something to be courageous about.
In this post we established the idea that stress is damaging
your nervous system, and we gave you a direct link to how excessive stress may
lead to depression. Further we’ve shown
that when you start to put the break on depression, you can shortcut the cycle
and may actually save your nerves and brain from further damage.
In our next post, we will go into ways that you can take
action to reduce stress and protect yourself against the negative health
consequences of depression.
Stay Tuned!
David
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