The Evolution of Depression

[Boerseun]

Animals evolve certain traits over immense stretches of time, because it's in some way beneficial to the species.

 

In breeding season, males posture, threaten and intimidate their fellows for access to females. Individuals stiffen their hairs to increase their apparent size, looking more threatening. Some reptiles inflate large flaps in their cheeks to achieve the same goal. Deer grow huge antlers, buffalo head-butt, lions charge and slap each other, but very rarely does this aggression result in violence where any individual gets seriously hurt - although it wastes an enormous amount of resources.

 

But there's an interesting off-shoot of this whole process. Amongst the pit vipers of America, for example, competing males rear up against each other, entwine, and try to push the other over. The first to fall is the loser, and he slithers away. But the females also emulate the male's intimidation strategy prior to mating: they also rear up and push against the males. Males who have lost their last battle of strength against another male, seem to have all the energy sucked from them - they make a halfhearted attempt at pushing, fall over, and despondently slither off. It seems that it takes them days to get over the humiliation of their defeat. Not interested in wimps, the female will then turn away and go and look for another more deserving, stronger male.

 

This process serves a very good purpose. It cuts down on unnecessary violence between males which might result in cuts (about as bad as intraspecific violence gets) which might get infected, leading to the individual's demise. The loser basically "advertises" his submissive status to the females by only putting up a half-hearted fight, and being pushed over by females half his size.

 

And this brings me back to the thread title.

 

Could it be that depression, which seems to be a negative trait, clearly not one to be selected for, has a positive role in evolution? Whatever the cause might be, once you're depressed, you make for very bad company. It's harder to pick up girls when you're depressed, as opposed to picking up girls left, right and center when you're happiness incarnate. Depression might be a sign telling females to "Stay Away - This Guy's a Loser" without you having to slug it out with an Alpha Male in front of the female, so that she can see you establish your status in the dominance hierarchy for herself? Basically, depression cuts down on unnecessary violence, making for a more stable society.

 

Of course, the reasons people get depressed vary. Even leaders in society (alpha males) get depressed. Sex and procreation is clearly not always the cause. But what I'm saying, is that the mechanism causing depression might have originated as part and parcel of establishing and maintaining a dominance hierarchy, saving on unnecessary bloodshed in that you have your status in the hierarchy pasted on your forehead through your depressive attitude and despondent nature without having to get involved in a fight every time a girl strolls by.

 

Makes sense?

 

If it does make sense, how would that trait then be bequethed to the next generation, except through kleptogamy? Which then makes for a completely new case for the evolution of criminal behaviour, and the shunning of the dominance hierarchy altogether...

[lemit]

Yes, that makes sense.

 

I have been treated, incorrectly, for depression several times. (I actually had a vitamin deficiency.)

 

The depression treatment gave me depression and gave me a chance to try to figure out the uses of depression. I got a feeling it was a way of healing and preparing the body and psyche for the next battle, such as the one against the doctor who had prescribed antidepressants. I thought it served that purpose well, since I could shuck it off in a few days by stopping the medication. I can see that, like an allergic reaction, it is normally excessive.

 

So yes, I can see the possibility of a natural use for depression.

 

--lemit

[InfiniteNow]

It's also plausible that we've selected for positive feelings, euphoria, happiness, etc. ...and that these have reinforced certain behaviors which led to increased reproductive success. Following from this, depression may just be an emergent property... the "lack" of those positive things which certainly did confer evolutionary benefit. Depression could just be "along for the ride," and not directly confer any evolutionary benefit itself. [/speculation]

 

Interesting idea, all the same. I hadn't considered it as a potential dominance/hierarchy mechanism.

[McBrayer]

Actualy is it a disease

[McBrayer]

Every one says if some body get stressed .... or become sad get depressed

[Boerseun]

After doing a bit more digging on the subject, it turns out that after losing a dominance fight (posturing, charging, threatening, etc.) the loser slows down his production of testosterone. It seems as if (like in the case of the Pit Vipers in the first post) the male's "depressed" attitude is not so much "depression" in the human sense, as much as merely a lowered inclination to get involved in any sort of mating activity, by merely having less testosterone coursing through its veins.

 

I'm not sure about any parallels between depression and testosterone production, though. It might be that I'm merely antropomorphizing symptoms that very much look the same.

[InfiniteNow]

Excellent point. Along similar lines, if your favorite sports team loses you're also likely to expereince a drop in testosterone levels.

 

So, for instance, your favorite soccer team makes it to the world cup. If they win, you experience a surge of testosterone. If they lose, you experience a drop.

 

Thinking about this testosterone link, I'm beginning to think you're quite right in that this is a hierarchy issue. Our favorite sports team can be equated with our "troop" or "pack." If our "troop" loses a fight to another troop, it's probably a more successful approach to be less aggressive toward that other troop in the future... and lower testosterone would encourage fewer aggressive exchanges with them.

 

I'm still contemplating how to tie this into the depression concept, but it sure makes sense that those organisms who avoided challenging a more dominant group over and over again probably did better evolutionarily than those organisms which continued challenging the more dominant pack over and over again... like a person who continues to touch the hot flame on their stove despite being burned repeatedly. The ones who stop touching the fire after the first burn tend to be better off than those who never learn that lesson and just keep burning themselves.

[HydrogenBond]

If you look at a drastic reality event, such as the loss of a close loved one, which can lead to depression, the memory grid containing that person, which was orientating one to an important aspect of their reality, is no longer valid in reality.

 

If you look at the symptoms of depression, the low energy and the more withdrawn orientation, sort of detaches the sensory systems from reality, preventing as much new data from entering via these systems.

 

Depression sort of restarts the brain in safe mode, after a system crash, detaching system devices, such as the video and audio cards, for safer restart. From safe mode the operating system and memory are checked for errors, until the brain can restart in full mode. Many of the errors, during system check, appear within the repetitive imagination of the depressed person, sort of like a recurring print out in the mind. Once one comes to terms with the needs of system check, the system restarts in full mode.

 

Drugs for depression can help to restart the system quickly after a fatal crash, but this may be like restarting a computer after a crash, without a system check. Not everyone wants to wait for the computer to check the hard drive for errors, before they get back onto the net. Often the system will reboot normally, with all the checks not really needed, but not in all cases.

 

Unfortunately for this smaller group, the data print out in the repetitive imagination, during safe mode restart, requires actions by the ego, who is often not skilled enough in brain programming to do the required tasks. If you don't push A the system hangs. Culture has added extra synthetic things to the natural memory structuring, that the brain can't fully deal with using the natural operating system. This means some manual programming could be be needed for some of the tweaks. Often professionals can help, especially those who have experience with safe mode.

[lemit]

Very good, Hydrogen.

 

Of course, I'm always a sucker for any use of electronic brains to help us understand our biological brains. But I've never seen the analogy taken so far so successfully. Good work.

 

--lemit