The Frontal Cortex

The Stress Spiral

Natalie Angier has an excellent column on the self-defeating feedback loop triggered by chronic stress. According to a new paper, when mice are chronically stressed, they end up reverting to habit and routine, even though these same habits are what led to the chronic stress in the first place:

Reporting earlier this summer in the journal Science, Nuno Sousa of the Life and Health Sciences Research Institute at the University of Minho in Portugal and his colleagues described experiments in which chronically stressed rats lost their elastic rat cunning and instead fell back on familiar routines and rote responses, like compulsively pressing a bar for food pellets they had no intention of eating.

Moreover, the rats’ behavioral perturbations were reflected by a pair of complementary changes in their underlying neural circuitry. On the one hand, regions of the brain associated with executive decision-making and goal-directed behaviors had shriveled, while, conversely, brain sectors linked to habit formation had bloomed.

In other words, the rodents were now cognitively predisposed to keep doing the same things over and over, to run laps in the same dead-ended rat race rather than seek a pipeline to greener sewers. “Behaviors become habitual faster in stressed animals than in the controls, and worse, the stressed animals can’t shift back to goal-directed behaviors when that would be the better approach,” Dr. Sousa said. “I call this a vicious circle.”

As I noted in this article, I think there’s increasing evidence that chronic stress plays a pivotal role in a wide variety of mental disorders, including depression. Stress works its ravages in large part by suppressing the release of trophic factors. in the brain. (Trophe is Greek for nourishment; what sunlight and water do for trees, trophic factors do for brain cells.) In a series of influential papers published earlier this decade, Ronald Duman at Yale demonstrated that the same destructive hallmark is seen in depression, so that our neurons are deprived of what they need. (From the perspective of evolution, this response makes sense: in chronically stressful conditions, it probably doesn’t make sense to invest in a lavish cortex.)

Obviously, there’s a huge gap between less robust brain cells and habit-loving mice, but I think the theme connects: chronic stress reduces cellular plasticity (including neurogenesis), which might make us (and mice) more likely to settle into familiar ruts and routines. The end result is that people stick with the very behaviors that created the stress in the first place.

This penchant for self-destructive routines also plays out at the level of everyday thought. I think there’s some intriguing evidence showing how being depression can make it that much harder to escape the mood disorder, as one gets stuck in a whirlpool of negativity. Consider some elegant work done by John Jonides and colleagues on an experimental exercise known as the “suppression task”. Subjects are given four random words, two of which are printed in blue and two in green. After reading the words, they’re told to forget all the blue words and remember all the green words. Then, the scientists provide a steady stream of “probe words” and ask the subjects whether or not each probe is one of the words they were asked to remember. Interestingly, Jonides has found differences between clinically depressed and control subjects on the suppression task. While people suffering from depression perform normally when trying to forget words with a positive association (“smile,” “sunny,” etc.), they’re much worse at forgetting words with a negative association, such as “hurtful” or “lonely”. This suggests that being depressed primes us to fixate on problems, on all the things that are wrong with us and the world. The end result is a recursive loop of miserable thoughts, which leads to more stress, and more misery.

The larger point of this research, of course, is that it’s imperative to seek medical help for serious cases of depression. It’s hard to escape a downward spiral by yourself.

Comments

  1. #1 becca
    August 18, 2009

    The best part of that study is definitely that fact that a 4 week vacation from stress helped the rats get back to normal.

  2. #2 OftenWrongTed
    August 18, 2009

    As a retired airline captain, I found that habit and routine are the stuff of daily flying: Use of checklists maintains continuity of flight. Flying “canned flight plans” saves time and fuel. The changes in enroute flight conditions, destination and alternate airport considerations will change only slightly over time, potentially a cocktail of stressors. I found that vacations spent surfing helped me get back to normal.

  3. #3 Judith
    August 18, 2009

    The even larger point of this research, of course, is that it’s imperative to seek psychological help for serious cases of depression. It takes great education, support, and reinforcement to change our ways of thinking and break this cycle – apart from the medical help of antidepressant drugs.

    Please don’t use “elegant” to describe good work. It’s an over-used word that you don’t need anymore.

  4. #4 Zoasterboy
    August 18, 2009

    Yes, how dare you use the word elegant. You don’t need it! Ever! Never! Hmph!

  5. #5 Was Once
    August 18, 2009

    Maybe so, but I also feel that drugs do let one become responsible for how they think. My brother put forth this— There is a belief we can medicate ourselves out of anything – any and all internal conflict must have resolution. – Nobody stops to think that maybe we become depressed when we need depression – that depression might be more of a kind of a “cure” than an “illness”.
    Maybe it(depression) will jump start you into changing behaviors.
    Just ideas.

  6. #6 Was Once
    August 18, 2009

    Maybe so, but I also feel that drugs do “NOT” let one become responsible for how they think.
    a typo…sorry

  7. #7 Amanda
    August 18, 2009

    In the last experiment you mentioned, was a second experimental group given obscenely positive/happy people who read the words in green and blue? Did those people tend to have trouble forgetting the optimistic/sunny words?

    I think words like “lonely” stick in the minds of the chronically depressed because they can relate very saliently with that word. Just like how the word “bird” would be harder to forget for you, because you have a spunky one.

    I think it’s true that the severely chronically depressed tend to “downward spiral,” but isn’t medical help usually unhelpful?

    (Aside: I think “elegant” is a fine word to use until Jonah invents something better. It’s just the best word to use to describe a creatively efficient and well-designed study. I don’t think he overuses it.)

  8. #8 Amanda
    August 18, 2009

    Let me try that first sentence again: In the last experiment you mentioned (green/blue words), was there a second experimental “positive/happy/not-depressed” group that was given positive/happy words? Did those people tend to have trouble forgetting the “positive” words?

    sorry for the gibberish writing: 14hr work days, chronically stressed = reason for the typos and reason why someone directed me to this article…

  9. #9 Art
    August 19, 2009

    Sounds to me like you have a link in why the right-wing has a habit of negative thoughts, attacks and an inability to let go of the negative claims and imagine a more positive world view and creative alternatives.

    The birthers, deathers and truthers are very much representatives of a demographic of middle and low class white males who feel a lot of pressure, loss of status and a loss of a role for them in the present economy. They are feeling a lot of stress.

    Their world view is very negative as they tend to think the worse of everyone who doesn’t share their views. They cannot seem to remember anything positive their opposition ever does and they cannot forget anything that has been done wrong even if the accusation is proved false.

    They are very much caught in a rut in terms of thought patterns and arguments but, at the same time, they are highly resistant to conceding any point or letting go of an argument even after it has been beat to death.

    Many seem to cleave to a romanticized view of previous times and evidence a desire to return to the ‘way thing were’.

    Your article offers seems to offer a good and plausible explanation for all of these points.

  10. #10 LRA
    August 19, 2009

    Well, we pretty much know that anxiety and depression go hand in hand…

  11. #11 "GrrlScientist"
    August 19, 2009

    i have bipolar disorder and when i am depressed, i often have trouble remembering colors, so this experiment would be silly since i remember words and numbers quite well, but colors often elude me.

  12. #12 Michael Porter
    August 19, 2009

    I have a friend who has PTSD and it is true, his brain kind of goes into a loop where he repeats patterns over and over. He does negative behaviors like drug use, and other things and he doesn’t know why he falls back on these destructive patterns. Maybe it is because, as you say, he is attached to self-destructive routines.

    Interesting article!

  13. #13 Astrid
    August 19, 2009

    This looks interesting. In my experience,there is some appeal in routiens when stressed (but then again, I’m autistic so maybe it’s more of an autism thing than a stress thing), so the routines/habits *seem* productive. But there is one thing I wonder, why are habits thought o be a source of stress? I didn’t understand that part.

  14. #14 Zoasterboy
    August 19, 2009

    I can see how this makes sense theoretically and first hand. Using amphetamine salts causes the inhibition of the re-uptake of Norepinephrine (a stress hormone). Using amphetamine will give me good concentration, energy, but conversely can lead me into thought loops where I will repeat a thought or activity. Perhaps these are the same neural pathways that are being activated on a larger scale while under stress?

    Last night I fell asleep a few hours after taking some adderall. When I woke up I was stuck with looping thoughts and feelings left over from my dream, I would think about a 12v and 15v AC to DC power adapter for some non-existent Play Station with 4GB of RAM. I would feel incredibly comfortable with the idea that it was being sold with a 15v adapter and then slowly become horrified thinking about it being sold with a 12v adapter. I still feel somewhat bothered by the thought. This habitual thought went on for a while and I had to force myself to stop thinking about it.

  15. #15 teiana
    August 19, 2009

    The worst part about being stuck in a stress loop is that people around you won’t ‘let’ you change. They make comments like ‘but you always do that’ or ‘well that’s just like you’.. Even if you manage to get away for four weeks, as soon as you get back, your environment is putting you back where you were. We seriously need more research though into the effects of chronic stress. Understanding this stuff will save lives i am sure. The question is how to simultaneously remove the causes of the stress, and break the negative habit loops, and change the environment so that the ‘new’ person can be allowed to grow and be accepted. Great article anyway.

  16. #16 Sean
    August 19, 2009

    Jonah,
    You are always so on point I just wanted to clarify something (being a psychologist).

    “The larger point of this research, of course, is that it’s imperative to seek MEDICAL help for serious cases of depression.”

    Evidence based, best practices indicates most efficacious alleviation, without relapse, of depressive symptoms with a combination of psychotherapy and medication. So when you said “medical” I just wanted to expand and clarify.

    I completely agree with the negative “loop”, I see it frequently in patients. Also of interest is patient’s negative perspective of emotionally ambiguous situations. I bet if they were given words with ambivalent/ambiguous valence they would remember them as negative…

  17. #17 Meg
    August 19, 2009

    Obviously the people who did this study weren’t depressed, or didn’t talk to people who suffer from severe, recurrent depression. All they had to do was ask and I could have told them ,”Yes, being depressed pulls you in to a deep rut, and the longer you’re in it, the harder it is to force your way out. The more depressed/stressed you feel, the darker things become in your mind.” Why make the rats suffer for the obvious?

  18. #18 donna
    August 23, 2009

    I’m bipolar and tend to think it is a problem of breaking the neuron chains responsible for negatice thoughts. What works for me is an anti-seizure drug, and since using it, I have never been depressed or become manic again.

    We need to look more at the cycling of thoughts, rather than labeling people as “depressed”.

  19. #19 John
    August 24, 2009

    Two points:

    1) Though they may be (e.g., self-medication to the point of dysfunction), habits are not necessarily self-destructive. Perhaps the Sousa experiment simply proves that stress drove the rats towards ‘comfort-seeking’ behaviors, which become more important under stressful conditions than ‘productive’ behaviors. Habits, after all, tend to form because they deliver results–perhaps just not the results expected from a ‘Type A’ observer.

    2) Regarding the conclusion in re: Jonides’ research “that being depressed primes us to fixate on problems,” it strikes me that the causal link here may be reversed. Doesn’t it make more sense that people who have a tendency to become depressed are sensitive (and thus affected by negative external events which stress them) or optimistic (and thus more likely to be disappointed about reality)? Another possible conclusion from these results is that ‘normal’ people tend towards sociopathy, being able (as most are) to blithely ignore reality in favor of constructs which enable them to maintain their bliss? If so, this would clearly be a rational adaptation.

  20. #20 Семен
    March 19, 2010

    Это прямо в точку!!! Иными словами и не скажешь! :)

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