
The evolutionary origin of depression - tokenadult
http://www.economist.com/sciencetechnology/displaystory.cfm?story_id=13899022
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miloshh
Interesting hypothesis. However, isn't depression sometimes getting in the way
of pursuing perfectly attainable goals? For example, finding more friends or
losing a bit of weight are definitely not overly ambitious goals, but
depressed people often despair that they will never be able to reach them.

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darshan
From the opening paragraph: _[He] likens the relationship between mild and
clinical depression to the one between normal and chronic pain. He sees both
pain and low mood as warning mechanisms and thinks that, just as understanding
chronic pain means first understanding normal pain, so understanding clinical
depression means understanding mild depression._

In other words, yes, people with clinical depression find that it gets in the
way of their daily life. His hypothesis is about why normal, healthy people
suffer from low mood / mild depression from time-to-time, and what
evolutionary advantage that might give us.

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pie
This is one of those concepts that I always simply assumed to be true.
Ordinary feelings of depression (i.e. specifically not chronic or "clinical"
depression) are quite normal responses to situations that are, in fact,
depressing. These feelings can help shake us out of situations we might
otherwise suffer through.

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Afton
This is interesting. I wonder if it means anything more than "depressive
people are those that are unable to let go of failure"? Seems like an apt
description of many generally depressed people I know.

Side note: Anyone have thoughts on whether 'depression' is an umbrella term
for distinct mental traits?

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tokenadult
_Anyone have thoughts on whether 'depression' is an umbrella term for distinct
mental traits?_

My sense of the evidence, as I read the masterwork on the subject

<http://www.amazon.com/gp/product/0195135792/>

just now for research I am doing, is that depression has multiple distinct
causes, and a variety of particular manifestations.

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rriepe
My theory on it is something between "pack" benefit and "individual" benefit.
I believe that depression is beneficial to pack hunters.

It goes like this: Operating in groups offers a great advantage. If a member
of the group is lost, however, there follows a period of time where the group
is more vulnerable. They haven't yet adapted (tactically) to a smaller group,
so business as usual could end up getting them killed.

A period of mourning, however, with lowered dangerous activity, puts the group
in less danger while they recoup from their loss. During this time they're
more likely to gain new members, train young ones or simply adapt their
tactics to fit their smaller numbers.

Think of it like this: Take Kobe off the team and the Lakers start to really
suck. However, let them fill the fifth spot and rethink their strategies...
and they start to look like a good team again.

~~~
TheSOB88
Seems true, but I think we're talkin about a different kind of depression here
than mourning over someone's death.

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b-man
I don't think the journalist did a good job when he took his conclusions as:

"Depression may turn out to be an inevitable price of living in a dynamic
society."

That amounts to, Hey, we are doing something that hurt us as a society, but
what the heck, lets all take the symptom of our mistake as a 'price' for our
'correct' path.

The blind leading the wounded.

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amichail
This will change in the future: everyone will know early on in life what their
capabilities are based on analysis of their DNA.

~~~
tokenadult
Do you really think that people can set all of their personal goals just from
knowing their genome?

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amichail
Your genome will give you critical information about the sorts of things you
would be good at.

For example, an analysis of your genome might tell you that you should pursue
a startup that makes use of sophisticated mathematics.

The specifics of that startup are up to you.

~~~
wjy
I think it would be much more effective to evaluate whether you're actually
good at sophisticated mathematics.

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tokenadult
Having thought about this article for a day, I'm wondering what the view of
the cited scientist is of elevated human mood states, those that correspond to
pathological states of hypomania and mania. One of the tricky issues in
treating depression is to avoid inducing mania.

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diN0bot
seems more likely to me that depression doesn't get in the way of survival and
reproduction.

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pwncat
I disagree with this argument. I think another one's more salient. For a pack
animal such as primal humans probably were, a certain type of moderate
depression is a survival mechanism for dealing with low social status. Your
appetite and libido decrease, you become inassertive, you accept mistreatment
from others. Subjectively, this process and experience sucks, but lacking
desire to mate with the alpha female keeps the omega male alive. Much more
importantly (since nature doesn't care much about unsuccessful individuals)
it's a survival mechanism for the _pack_ ; the depressive response ensures
that, in extreme scarcity, the less successful individuals slink away and
accept starvation, rather than challenging and potentially causing harm to the
more important ones.

In modern society, this reaction is completely useless and utterly
maladaptive. It also has a tendency to fire in people at all levels of social
status, because modern society (with its dynamic, subtle, and multileveled
play of social status) is confusing to the primal mind. So a depressive
response can be rightly considered an illness.

Civilization expects everyone to assume the role most closely analogous to
high beta/low alpha. People who have omega traits tend to be depressives;
people who have too many alpha traits are sociopaths.

~~~
pfedor
_Much more importantly (since nature doesn't care much about unsuccessful
individuals) it's a survival mechanism for the pack_

I am not a biologist, but according to (what I understood of) "The Selfish
Gene" and the like, the natural selection takes place on the level of genes.
Since the successful reproduction of a gene is usually (barring some
exceptional situations mentioned in the book) tightly coupled with the fate of
the individual carrying the gene, reasoning about natural selection that
operates on individuals typically leads to correct conclusions. Reasoning
about natural selection on packs is on the other hand typically incorrect, if
it leads to conclusions different from the individuals-based selection.

In your example, if you imagine two genes, one that tells the low status
carrier to accept starvation, and the other that tells its carrier to fight
for dear life no matter what its social status, the second gene will win and
the first one will go extinct, even if from the point of view of the whole
pack the first gene could be better.

This is not to say that your hypothesis is invalid, as I'm sure it can be
rephrased in terms of genes/individuals without losing the core message.

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jballanc
Ok, well... I _am_ a biologist and one of the first things you need to
understand about "The Selfish Gene" is that much of what Dawkins presents as
fact is very much under dispute in the biological research community. Be very
cautious about accepting anything he presents as "the one true way" of
understanding evolution. It is anything but!

One term you can Google for more information is "multi-level selection". I
find the pack animal explanation actually rather interesting. It meshes well
with some of the research that I'm doing on evolution as targeted at resource
utilization efficiency. I think the real question is to what extent primitive
man was a "pack" animal as opposed to a "group" or "tribe" animal. That is, I
think there are many open ended questions regarding the social structure of
early man (for one thing, if early man was a pack animal you'd have to explain
the origin of monogamy, or at least limited polygamy, in place of the harem
structure of most pack animals).

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mdemare
Evolution is essentially an algorithm. That's why we can use logic to predict
that genes that regulate behavior for "less successful individuals to slink
away and accept starvation" are unlikely to arise, since not a single one of
the ancestors of that individual were less successful and slunk away to accept
starvation.

~~~
jballanc
There's a mister Hardy and a mister Weinberg that would like to have a word
with you about that logic...

<http://en.wikipedia.org/wiki/Hardy-Weinberg>

The other thing to keep in mind is that evolution works as a movement through
nucleotide space over a fitness landscape. The fundamental flaw in much of
Dawkins work is his reliance on a biologically unrealistic definition of a
"gene". Sure, if you go with his definition of genes then logic can tell you
all sorts of things about evolution that aren't necessarily true.

