Monday, November 12, 2012

The bipolar disorder pendulum: Depression as a compensatory adaptation

As far as explaining natural phenomena, Darwin was one of the best theoretical researchers of all time. Yet, there were a few phenomena that puzzled him for many years. One was the evolution of survival-impairing traits such as the peacock’s train, the large and brightly colored tail appendage observed in males.

Tha male peacock’s train is detrimental to the animal’s survival, and yet it is clearly an evolved trait ().

This type of trait is known as a “costly” trait – a trait that enhances biological fitness (or reproductive success, not to be confused with “gym fitness”), and yet is detrimental to the survival of the individuals who possess it (). Many costly traits have evolved in animals because of sexual selection. That is, they have evolved because they are sexy.

Costly traits seem like a contradiction in terms, but the mechanisms by which they can evolve become clear when evolution is modeled mathematically (, ). There is evidence that mental disorders may have evolved as costs of attractive mental traits (); one in particular, bipolar disorder (a.k.a. manic-depression), fits this hypothesis quite well.

Ironically, a key contributor to the mathematics used to understand costly traits, George R. Price (), might have suffered from severe bipolar disorder. Most of Price’s work in evolutionary biology was done in the 1970s; toward the end of his life, which was untimely ended by Price himself. For many years he was known mostly by evolutionary biologists, but this has changed recently with the publication of Oren Harman’s superb biographical book titled “The Price of Altruism: George Price and the Search for the Origins of Kindness” ().

Bipolar disorder is a condition characterized by disruptive mood swings. These swings are between manic and depressed states, and are analogous to the movement of a pendulum in that they alternate, seemingly gravitating around the "normal" state. See the figurative pendulum representation below, adapted from a drawing on

Bipolar disorder is generally associated with creative intelligence, which is a very attractive trait (). Moreover, the manic state of the disorder is associated with hypersexuality and exaggerated generosity (). So one can clearly see how having bipolar disorder may lead to greater reproductive success, even as it creates long-term survival problems.

On one hand, a person may become very energetic and creative while in the manic state. This could be one of the reasons why many who suffer from bipolar disorder have fairly successful careers in fields that require creative intelligence (), which are many and not restricted to fields related to the fine and performing arts. Creative intelligence is highly valued in most knowledge-intensive professions ().

On the other hand, sustained acute mania or depression are frequently associated with serious health problems (). This is why the clinical treatment of bipolar disorder often starts with an attempt to keep the pendulum from moving too far in one direction or another. This may require medication, such as clinical doses of the elemental salt lithium, prior to cognitive behavioral therapy. The focus of cognitive behavioral therapy is on changing the way one sees and thinks about the world, particularly one’s “social world”.

Prolonged acute mania, usually accompanied by severely impaired sleep, may lead to psychosis. This, psychosis, is an extreme state characterized by hallucinations and/or delusions, leading to hospitalization in most cases. It has been theorized that depression is an involuntary compensatory adaptation () aimed at moving the pendulum in the other direction, out of the manic state, before more damage ensues ().

Elaborate approaches have been devised to treat and manage bipolar disorder treatment that involve the identification of mania and depression “prodromes” (), which are signs that a full-blown manic or depressive episode is about to start. Once prodromes are identified, cognitive behavioral therapy techniques are employed to prevent the pendulum from moving further in one direction or the other. The main goal of these techniques is to change one’s way of thinking about various issues (e.g., fears, pessimism). These techniques take years of practice to be used effectively.

Identification of prodromes and subsequent use of cognitive behavioral therapy seems to be particularly effective when dutifully applied with respect to manic episodes (). The reason for this may be related to one interesting fact related to bipolar disorder: manic episodes are not normally dreaded as much as depression episodes.

In fact, many sufferers avoid taking medication because they do not want to give up the creative and energetic bursts that come with manic episodes, even though they absolutely do not want the pendulum to go in the other direction. The problem is that, if depression is indeed a compensatory adaptation to mania, it seems reasonable to assume that extreme manic episodes are likely to be followed by extreme episodes of depression. Perhaps the key to avoid prolonged acute depression is to avoid prolonged acute mania.

As someone with bipolar disorder becomes more and more excited with novel and racing thoughts (a prodrome of mania), it would probably make sense to identify and carry out calming activities – to avoid a fall into despairing depression afterwards.


Amber O'Hearn said...

That makes sense.

I also like the orchid theory. It also explains psychiatric disorders as evolutionarily motivated:

"These bad genes can create dysfunction in unfavorable contexts—but they can also enhance function in favorable contexts."

It's a social group mechanism, that works best when it is rare: "The many dandelions in a population provide an underlying stability. The less-numerous orchids, meanwhile, may falter in some environments but can excel in those that suit them."

On the other hand, my own bipolar tendencies go into full remission on an all-meat diet, so I think part of it is truly a pathological response to an inappropriate food environment, i.e. illness. I'm no longer crippled by it at all anymore. I still experience high creative intelligence, though. :-)

Unknown said...

80% of the time in bipolar I disorder, an episode of one polarity is followed by an episode of the other. Timing can be highly variable, however. The depression can also have characteristic psychotic symptoms (delusions of being posessed, or of dissolving, or somatic delusions). They are coming much closer to getting some of the genetics responsible elucidated. Over time, multiple episodes seem to cause damage in the brain, and in later life many folks with bipolar disorder have cognitive problems similar to ADHD. It is thought that treatment will ameliorate some of the damage, but that is not known for sure. Modern research therapy for bipolar disorder is much more focused on lifestyle modification, stress reduction, sleep hygiene, etc to reduce episodes.

Ned Kock said...

Hi Amber. Your experience re VLC (all-meat diet) reminds of a study I blogged about here showing a link between stress and blood glucose:

Stress seems to be a trigger of manic episodes.

Ned Kock said...

Thanks Emily. I remember we talked a bit about this earlier this year in Boston.

Puddleg said...

There is an excellent account of Price's life and work in the last part of the 3 part TV series "All Watched Over by Machines of Loving Grace".
This was the best TV series on science I've seen in a long, long time. Everything about it was novel and thought-provoking, yet deeply human.

Ned Kock said...

Thanks George. There is a full article on this BBC series on Wikipedia:

Videos of the full series are available from this link:

They start talking about Price at about 19 minutes into the third episode, the one titled “The Monkey in the Machine and the Machine in the Monkey”. He is really one of the “intellectual stars” of the third episode, even though the episode is not all about him.

Toward the end, at around 54 minutes, you can even see an old clip with Hamilton – considered by many the greatest evolutionary biologist since Darwin.

Ned Kock said...
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Ned Kock said...

I was positively impressed by how Price was portrayed as one of the “intellectual stars” of the third episode of the BBC series, but a bit disappointed that his apparent selfless behavior and eventual suicide were presented as semi-rational attempts to test his own theory.

Having said that, I can see how this presentation would work well for a TV series, a stage play (e.g., Craig Baxter’s “The Altruists”), and even a movie that would rival “A Beautiful Mind”.

By the way, the link below is to an article by James Schwartz, probably the first to successfully bring Price’s story to the public attention.

In my opinion, there is a very good chance that Price would have survived had he had the access to the mental health resources that are available today in London (where he committed suicide) and in most large cities.

Even some basic care could have prevented his untimely death. Price’s diet was really bad prior to his suicide, which was reflected in his very poor health. His behavior was consistent with that of someone who needed help. Harman’s book goes into a lot of detail on that.

wartrol works said...

They are arriving much nearer to getting some of the genes accountable elucidated. Over time, several periods seem to cause harm in the mind, and in later life many people with bpd have intellectual problems just like ADHD.

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They are arriving much nearer to getting some of the genes accountable elucidated. Over time, several periods seem to cause harm in the mind, and in later life many people with bpd have intellectual problems just like ADHD.

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David Isaak said...

Bipolar disorder gets all the attention, but most creative people I know are more cyclothymic, which is kind of like bipolar without the psychosis.

It seems to me to be especially common in writers. From the outside, what it looks like is someone who has productive periods interspersed with periods of where there is a tendency toward depression and an inability to get things done. Most people who live with this sort of thing perceive themselves as a normal person with a tendency toward depression--when in fact their productive periods are a form of hypomania rather than the ground state. (I speak from some degree of personal experience here.)

Maybe it's like Sickle Cell Disease? If you get one set of the genes, it's cyclothymia: Useful and not all that costly. But if you get a set from both parents, yo get full-on BPD, which is quite costly.

In that case, it might not be BPD that is selected for. Could it be that cyclothymia is selected for, and BPD is a pathological consequence in some unlucky individuals?

Just a thought.

Ned Kock said...

Hi David. Cyclotymia may be the form that has been selected for, with BPD being an exacerbation caused by modern diets and lifestyles.

Cyclotymia is frequently referred to as a “mild” form of BPD, but there are different schools of thought on this. I am exposed to some of this thinking by being in contact with several psychologists that are using WarpPLS in their analyses, some of whom also work as psychotherapists. Some of my research collaborators are also psychologists (several of the chapter authors in my edited book “Evolutionary Psychology and Information Systems Research” are psychologists).

The opinion that cyclotymia is a “mild” form of BPD is not universally held, because in cyclotymia the bipolar swings are less acute, but much more frequent. It is not uncommon for sufferers to experience it as something like permanent low grade depression – again, most people dread (and thus notice) the depressive stages.

Theoretically, it is possible that cyclotymia is a further step in the compensatory adaptation process, where broad pendulum swings are averted at the expense of small but more frequent swings.

Puddleg said...

I think I have been cyclothymic for most of my life, but it has disappeared after adapting to a paleo, low carb diet. And I miss it in some ways. It is highly adaptive if you need to get noticed to survive. It enhances your ability to convince others, which makes it perfect for leadership or creative endeavour. The downtime is ideal for research if you're a reader, or contemplation - I don't read as much now as I used to when in the low part of the cycle.
It would be excellent for passing on genes if it was focused on romantic cycling of partners, as I'm sure it is in many cases.
Cyclothymia is a risky strategy and a stressful one for some types or in some environments - it's not a superpower.
But sometimes it sure felt like one.

Puddleg said...

I see cyclothymia as the form bipolar disorder takes in someone who is genetically or otherwise protected from experiencing psychosis (in the hypomanic phase) and from suicidal ideation (in the depressive phase).

I don't think cyclothymia is rapid cycling necessarily, tho perhaps the cycles are not nearly as long or as deep as they can be for BPD. But weekly (or thereabouts) cycles don't seem rapid when you're experiencing them. There's usually enough time to exhaust the possibilities of the state and long for a change.

shtove said...

Ned, a while ago you promised a post on cheese & waist-expansion.

Did I miss that?

Thanks for the blog. Given me a lot to chew over.

Ned Kock said...

Thanks for the reminder shtove – it is in my list of topics to blog about, high in the list.

Puddleg said...

In fact, i'll hypothesise that cyclothymia is the gene combo that is selected for, and BPD is the less adaptive result of it combining with schizotypal and/or depressive-inflammatory types of genes, which may be adaptive in their own way, but the full trifecta, not so much.

Puddleg said...

but what is the evolutionary meaning of an adaptation that only becomes florid when an industrial diet is available?
We should be looking at the equivalent of BPD in a healthy traditional setting.
Creativity, inventiveness, language skills?
The great composers and writers in classical times were often tortured souls - Carravagio, Beethoven - but they kept creating, and only in more recent times do we find their equivalents becoming periodically unproductive through the effects of modern forms of mental illness.

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Anon said...

Interesting post, Ned.

This may sound odd, but I'm thinking it's relevant: About a decade ago, I was at a dance, and met a girl I thought was extremely attractive. I got her number and we wound up meeting for coffee at a Starbucks.

I noticed that her mom had driven her there, and was waiting in the parking lot to take her home afterwards. This seemed odd to me, as the girl was well into her twenties.

The girl explained that she was bipolar, lived at home because of it, and that her mom didn't trust her to go out on unchaperoned dates of any kind. (It was implied this was because of past events, but I didn't pry.)

Here's what I'm getting at: The coffee lasted maybe half an hour. And during that short period, I became more attracted to her than I'd ever been to anyone in my life. I mean, to the degree that it really frightened me. I was attracted to her -- to be clear, wanted to have sex with her -- to an extent that it felt like a mental illness was coming over me.

It scared the crap out of me, and I never saw her again.

I've read many anecdotes about how sexually charismatic bipolar people can be, but nothing prepared me for the actual experience.

Anyway, this makes me wonder if attempts to explain reproductive success in bipolar disorder as a function of "creativity" or "productivity" might not be missing the forest for the trees.

I think people are attracted to them them because there is something about the disease that impels others to be so.

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Ned Kock said...

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