Evolution of Depression

[Dancing David]

something interesting in NS a couple of weeks ago...[i'll try to find it if others are interested]

was on how people with severe depression [with suicidal thoughts] have a serious impairment to their ability to imagine future events. That is to say, they can appreciate that future events will happen, but have an inability to place themselves in those events. It's as if the brain shuts down any long-term planning from a biological sense - and so the old adage "take one day at a time" as advice for coping with trauma, is actually enacted upon us by our brain chemistry.....

Well, I don't know, they can certainly imagine all sorts of negative things happening to them in the future. Some people will have less cognition, some will have more when severely depressed.

It is an interesting idea however. Long term planning is probably messed with by hopelessness.

 

[aggle-rithm]

I think it is a little simplistic to think of depression purely as low serotonin levels and I am not even sure that this has been experimentally confirmed - rather just inferred from the type of drugs which have some success in treating depression. Someone with more current knowledge might be able to correct me if I am wrong. I thought the general idea was less about levels of serotonin per se, and more about individuals sensitivity to serotonin - ie that some people need more of the neurotransmitter than others because of this insensitivity.

Secondly, there are more neuro transmitters than serotonin that are implicated. SSRI's don't work on everyone with depression - myself included. I only get a benefit from drugs which alter noradrenalin (eg venlafaxine, mirtazepine, possibly some tricyclics). SSRIs have no effect on me.

Seratonin levels are not the whole story by any means.

ETA: Having just done a search of publications in the area, I have discovered that my understanding of serotonins role in depression is also hopelessly simplistic!

True -- I worded my post badly. What I meant to say is that there is a correlation between serotonin levels in humans and depression in humans, and there is also a correlation between serotonin levels in adult mammals and aggression/hypervigilance in adult mammals. There isn't necessarily a cause/effect relationship, but I find the correlation interesting.

 

[aggle-rithm]

Also, possibly pertinent - I recall reading in cognitive and social psychology books that people who are feeling depressed perceive the world in a more objectively correct way than do people who are not depressed. (That is to say, they are less subject to biases of observation.) Is this correct and, if so, could depression be a means of driving people to change toward a more realistic appreciation of their situation in life?

This sounds like Freud's attitude towards depressed patients, who, he thought, were the only ones who had the mental clarity to realize how worthless they really were.

Depression can may you take a bleakly reductionist view of reality (I speak from experience here), but it's a distorted view that impairs normal functionality.

 

[andyandy]

Well, I don't know, they can certainly imagine all sorts of negative things happening to them in the future. Some people will have less cognition, some will have more when severely depressed.

It is an interesting idea however. Long term planning is probably messed with by hopelessness.

i can't find the article on the NS website....but i'll keep looking...

this is something interesting that did come up....

With some illnesses, such as diabetes, a simple test can usually quantify how severe a person's condition is, but depression is more complicated. The condition has been linked to a shrunken hippocampus, a part of the brain that also plays a role in spatial memory, so Neda Gould at the US National Institute of Mental Health in Bethesda, Maryland, and her colleagues wondered whether a video game that tests spatial memory could help measure the severity of the illness.

To test their idea the researchers developed a game based on some scenes from Duke Nukem, a game in which players navigate around a virtual town. The participants, who were already familiar with the town, were asked to find their way to as many landmarks as possible within a set amount of time.

Depressed people found their way to an average of 2.4 locations compared with 3.8 locations for healthy controls. Indeed, the more depressed a person was, the lower the score (The American Journal of Psychiatry, vol 164, p 516). Gould hopes the test may eventually provide a quantifiable measure of depression.

http://www.newscientisttech.com/channel/tech/dn11351-video-game-may-help-detect-depression.html

 

[Dancing David]

The isue as I se it is that depression can manifest in many ways, being part of a complex system. There are many different ways people respond to depression, so not all people will have a reduction is cognitive tasks, although I am not suprised that they didn't find as many lanmarks on the video game.

But here is the deal, measiuring depression would require a number of scales, and then a composite rating.

I am someone who has had major depression since I was twelve years old. And my cognitive abilities vary with the phase of depression that i am in. At times I can over concentrate and read in very distracting enviroments. At other times I am very easily distracted , it is part of the overwhelmed stuff where I just can't screen and narrow my focus.

The one thing i do know that antidepressant have done, is they have wrecked my memory. Which for me is a good thing, I had obesseive memory and anxiety in all my memories so loosing my memory has been a good thing, if somewhat annoying.

So I would argue that a number of tests that are used to generate a composite score would be the best.

Like how the operson identifies emotions in a series of pictures, thier anxiety response to graded levels of stimuli and many many others.

Reaction time will be slowed in most as will recall functions of cognition.

I have stated in the past that the main problem with tools like the Beck Depression Inventory is that they only measure gross severe depression, they are not as finely tuned as they could be.

 

[calebprime]

I think this research was flawed in that it looked at very mildly depressed students. It did indeed find that these people were more accurate in their perception of their own performance in a task, with "normal" people over estimating themselves. However, i think it was repeated in a more representative clinical population which found that more severely depressed people were just as inaccurate in under estimating their performance.

I think it is a little simplistic to think of depression purely as low serotonin levels and I am not even sure that this has been experimentally confirmed - rather just inferred from the type of drugs which have some success in treating depression. Someone with more current knowledge might be able to correct me if I am wrong. I thought the general idea was less about levels of serotonin per se, and more about individuals sensitivity to serotonin - ie that some people need more of the neurotransmitter than others because of this insensitivity.

Secondly, there are more neuro transmitters than serotonin that are implicated. SSRI's don't work on everyone with depression - myself included. I only get a benefit from drugs which alter noradrenalin (eg venlafaxine, mirtazepine, possibly some tricyclics). SSRIs have no effect on me.

Seratonin levels are not the whole story by any means.

ETA: Having just done a search of publications in the area, I have discovered that my understanding of serotonins role in depression is also hopelessly simplistic!

(cheerleader mode.) interesting/good discussion, folks.

I particularly like Prof. Yaffle's posts here. It's a key point that only mildly depressed people are more realistic.

A lot of confusion is caused by the public's concept of depression vs. doctors. We in the public throw the word around loosely.

 

[Professor Yaffle]

(cheerleader mode.) interesting/good discussion, folks.

I particularly like Prof. Yaffle's posts here. It's a key point that only mildly depressed people are more realistic.

A lot of confusion is caused by the public's concept of depression vs. doctors. We in the public throw the word around loosely.

To be honest, I think if we were all realistic about everything all the time, that would be enough to make us mildly depressed...

I think it is patently obvious to anyone with experience of moderate to severe depression that the "more realistic/accurate" theory is nonsense. If my thinking when depressed was actually a realistic interpretation of the world, then what happened after the depression would have been significantly different.

In fact one of the best psychological treatments for depression (CBT) mainly works by helping us to correct our biased thinking and completely unrealistic way of looking at the world when depressed.

 

[Mojo]

You might as well ask what purpose diabetes serves.

It selects for people who aren't predisposed to use CAM.

 

[Corpse Cruncher]

I don't know if anyone's made this point, but here goes.

Depression in humans is often accompanied by low seritonin levels. Low seritonin is also a mark of adulthood in many (if not all) mammalian species. The result of lower seritonin levels in the wild is that adults are more cautious and aggressive than youngsters, and thus are given a clear survival advantage.

Humans are unusual in that they are pedomorphic (retain childlike attributes into adulthood), so low seritonin in human adults is maladaptive.

If that was true, wouldn't that make depression a natural human progressive state rather than an illness?

 

[Dancing David]

To be honest, I think if we were all realistic about everything all the time, that would be enough to make us mildly depressed...

I think it is patently obvious to anyone with experience of moderate to severe depression that the "more realistic/accurate" theory is nonsense. If my thinking when depressed was actually a realistic interpretation of the world, then what happened after the depression would have been significantly different.

In fact one of the best psychological treatments for depression (CBT) mainly works by helping us to correct our biased thinking and completely unrealistic way of looking at the world when depressed.

Yay!

Hear, here!

 

[Professor Yaffle]

Ooooh, I suddenly seem to have acquired a fan club....