Is Depression an Adaptation?
Jonah Lehrer argues in the New York Times Magazine that depression might be good for us. He's popularizing a theory advanced by two Virginia researchers who claim that depression is an adaptive mechanism that compels us to withdraw from the world and focus intently on our problems.
The fact that depression is so common strikes him as an evolutionary paradox. About 7 percent of adults will experience some depression in any given year, according to Lehrer's statistics. We know that at least some kinds depression have a heritable component, i.e., that genes help explain why depression strikes some and not others. At first glance, depression seems obviously detrimental to fitness. Every classic symptom seems to hurt a sufferer's chances of passing on her genes: Depression saps productivity and decreases mental accuity. Depressed people lose interest in food, socializing, and even sex. Depressed parents may struggle to care for their children. Hardly a recipe for fitness. So, why did such terrible genes persist?
But Lehrer thinks he sees a silver lining:
The alternative, of course, is that depression has a secret purpose and our medical interventions are making a bad situation even worse. Like a fever that helps the immune system fight off infection — increased body temperature sends white blood cells into overdrive — depression might be an unpleasant yet adaptive response to affliction. Maybe Darwin was right. We suffer — we suffer terribly — but we don’t suffer in vain.
Lehrer is arguing for an evolutionary take on the so-called analytical rumination model of depression. On this view, what we call "depression" is an evolved mechanism for forced, intensive introspection. His two main sources are psychiatrist Andy Thompson and evolutionary psychologist Paul Andrews. In an influential paper published in Psychological Review in 2009, the two argue that depression is a suite of body responses designed to promote rumination, which they see as a form of intensive problem-solving. There is no doubt that rumination is a classic depressive thought pattern. Thompson and Andrews point to new research in neuroscience that is starting to unravel the brain mechanisms that underlie rumination. Psychologists have known for a long time that those who are predisposed to dwell at length on their problems are at higher risk of depression. Now, neuroscience is giving us a better sense of what's going on in their brains when they do so.
Thompson and Andrews summarize the analytical rumination hypothesis as follows:
In summary, we hypothesize that depression is a stress response mechanism (a) that is triggered by analytically difficult problems that influence important fitness-related goals; (b) that coordinates changes in body systems to promote sustained analysis of the triggering problem, otherwise known as depressive rumination; (c) that helps people generate and evaluate potential solutions to the triggering problem; and (d) that makes trade-offs with other goals to promote analysis of the triggering problem, including reduced accuracy on laboratory tasks. Collectively, we refer to this suite of claims as the analytical rumination hypothesis. [Psychological Review, 2009]
The glaring problem with this theory is that rumination is not particularly conducive to insight or problem-solving. Quite the opposite, in fact. The term derives from the Latin word for cud-chewing. One of the most widely used definitions of rumination is: "Repetitively thinking about the causes, consequences, and symptoms of one's negative affect." Another influential definition is: "repetitive thinking about sadness, and the circumstances of one's sadness." So, according to many influential definitions, rumination isn't necessarily even geared towards solving problems. A lot of rumination is just feeling bad about feeling bad.
As a psychiatrist, Thompson noticed that many of his depressed patients were preoccupied by genuinely difficult problems, such as whether to leave a bad marriage or change careers in mid-life. Sometimes ruminations have the form of serious questions, e.g., "Why did my husband leave me?" If someone figures out why her last relationship foundered, she might do better next time. On the other hand, a lot of rumination involves dwelling endlessly on the past or other things beyond the person's control. Many classic ruminative "questions" aren't necessarily questions at all. Consider the depressed person who keeps asking "Why am I such a loser?" That's not not serious introspection in the name of personal growth, it's self-flagellation disguised as reflection. The researchers say that depression is a way to focus on analytically complex problems. But they don't give us any evidence that people with more complicated problems are more likely to get depressed. Nor do they explain why depression persists for such a long time. Even the most complicated career and relationship problems don't usually require weeks or months of single-minded contemplation. A lot of depressing problems are pretty banal. Getting over getting dumped is hard, but you don't necessarily need high-powered analysis to do it. The ruminative theory also ignores the fact that, while some depression is clearly a reaction to a identifiable problem, many cases have no obvious external trigger.
One of the leading experts on rumination, Yale psychology professor Susan Nolen-Hoeksema, explains why rumination is a terrible coping strategy, whether you're depressed or not:
Many ruminators stay in their depressive rut because their negative outlook hurts their problem-solving ability, said Nolen-Hoeksema. According to her research, they often struggle to find good solutions to hypothetical problems. For example, if a friend is avoiding them, they might say, "Well, I guess I'll just avoid them too." In addition, ruminators express low confidence in their solutions and often fail to enact them--for example, failing to join a bereavement support group despite intending to, said Nolen-Hoeksema.
"Even when a person prone to rumination comes up with a potential solution to a significant problem, the rumination itself may induce a level of uncertainty and immobilization that makes it hard for them to move forward," she said. [APA Monitor]
Bouts of rumination would only have survival value if ruminators reliably came up with better solutions than non-ruminators and put them into practice. Yet the evidence suggests that rumination is more associated with paralysis than insight or action.
Thompson and Andrews cite experimental evidence that low mood can be conducive to analytical thinking. That said, rumination isn't usually very analytical in the ordinary sense of the term. An analytical thinker takes a problem apart in an orderly sequence and solves the sub-problems one by one. That's pretty much the opposite of rumination. Ruminators rehash the same negative thoughts over and over again without gaining insight or leading to any kind of conclusion. Successful analysis traces a line from premise to conclusion. Rumination just goes around and around in the same vicious circle.
It's easy to see why a capacity for intensive introspection or analytical problem-solving would have survival value. However, we also know that people think this way all the time without becoming clinically depressed. Highly analytical thinkers are at increased risk of depression. But that suggests that depression is a malfunction rather than an adaptation. The systems that give us useful cognitive abilities can also cause us pain when they go awry. If analytical thinking and sustained attention reliably yield life-saving insights, insightful people will pass on their genes.
Besides which, if contemporary experience is any guide, depression doesn't necessarily impair survival that much. It's usually self-limiting and fatalities are relatively rare. Though, as Echidne of the Snakes points out, we really don't know what the ancestral condition was like. We shouldn't assume, for example, that depression was as common in those days as it is now. Obesity is common today, but it was almost certainly rare for most of human history because we evolved in an environment where food was much less plentiful. Obesity is only a widespread problem today because we've created an environment that's very different than the one we evolved in. If depression was rare in the ancestral condition, and the capacity for introspection was beneficial, then there's no evolutionary mystery to solve.
Northwell Health CEO Michael Dowling has an important favor to ask of the American people.
- Michael Dowling is president and CEO of Northwell Health, the largest health care system in New York state. In this PSA, speaking as someone whose company has seen more COVID-19 patients than any other in the country, Dowling implores Americans to wear masks—not only for their own health, but for the health of those around them.
- The CDC reports that there have been close to 7.9 million cases of coronavirus reported in the United States since January. Around 216,000 people have died from the virus so far with hundreds more added to the tally every day. Several labs around the world are working on solutions, but there is currently no vaccine for COVID-19.
- The most basic thing that everyone can do to help slow the spread is to practice social distancing, wash your hands, and to wear a mask. The CDC recommends that everyone ages two and up wear a mask that is two or more layers of material and that covers the nose, mouth, and chin. Gaiters and face shields have been shown to be less effective at blocking droplets. Homemade face coverings are acceptable, but wearers should make sure they are constructed out of the proper materials and that they are washed between uses. Wearing a mask is the most important thing you can do to save lives in your community.
Two massive clouds of dust in orbit around the Earth have been discussed for years and finally proven to exist.
- Hungarian astronomers have proven the existence of two "pseudo-satellites" in orbit around the earth.
- These dust clouds were first discovered in the sixties, but are so difficult to spot that scientists have debated their existence since then.
- The findings may be used to decide where to put satellites in the future and will have to be considered when interplanetary space missions are undertaken.
What are they?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xODgyMDA0NC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNTM1ODc0Mn0.NH33LuauIo__sUBi4tvhwxDcsvhflDFD-Nhx9FjlSNk/img.jpg?width=1245&coordinates=148%2C0%2C149%2C0&height=700" id="cec96" class="rm-shortcode" data-rm-shortcode-id="acb78abe2ab46a17e419ad30906751d6" data-rm-shortcode-name="rebelmouse-image" />
Artist's impression of the Kordylewski cloud in the night sky (with its brightness greatly enhanced) at the time of the observations.
G. Horváth<p>The<a href="https://en.wikipedia.org/wiki/Kordylewski_cloud" target="_blank"> Kordylewski clouds</a> are two dust clouds first observed by Polish astronomer Kazimierz Kordylewski in 1961. They are situated at two of the <a href="https://www.space.com/30302-lagrange-points.html" target="_blank">Lagrange points</a> in Earth's orbit. These points are locations where the gravity of two objects, such as the Earth and the Moon or a planet and the Sun, equals the centripetal required to orbit the objects while staying in the same relative position. There are five of these spots between the Earth and Moon. The clouds rest at what are called points four and five, forming a triangle with the clouds and the Earth at the three corners.</p><p>The clouds are enormous, taking up the same space in the night sky as twenty lunar discs; covering an area of 45,000 miles. They are roughly 250,000 miles away, about the same distance from us as the Moon. They are entirely comprised of specks of dust which reflect the light of the sun so faintly most astronomers that looked for them were unable to see them at all. </p><p>The clouds themselves are probably ancient, but the model that the scientists created to learn about them suggests that the individual dust particles that comprise them can be blown away by solar wind and replaced by the dust from other cosmic sources like comet tails. This means that the clouds hardly move but are <a href="https://www.nationalgeographic.com/science/2018/11/news-earth-moon-dust-clouds-satellites-planets-space/" target="_blank">eternally changing</a>. </p>
How did they discover this?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xODgyMDAzNi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1Nzc4MjQ4MX0.7uU9OqmQcWw5Ll1UXAav0PCu4nTg-GdJdAWADHanC7c/img.jpg?width=1245&coordinates=0%2C180%2C0%2C181&height=700" id="952fb" class="rm-shortcode" data-rm-shortcode-id="a778280a20f1c54cd2c14c8313224be2" data-rm-shortcode-name="rebelmouse-image" />
"In this picture the central region of the Kordylewski dust cloud is visible (bright red pixels). The straight tilted lines are traces of satellites."
J. Slíz-Balogh<p>In their study published in the <a href="https://academic.oup.com/mnras" target="_blank">Monthly Notices of the Royal Astronomical Society</a>, Hungarian astronomers Judit Slíz-Balogh, András Barta, and Gábor Horváth described how they were able to find the dust clouds using polarized lenses.</p><p>Since the clouds were expected to polarize the light that bounces off of them, by configuring the telescopes to look for this kind of light the clouds were much easier to spot. What the scientists observed, polarized light in patterns that extended outside the view of the telescope lens, was in line with the predictions of their mathematical model and ruled out other possible sources. </p>
Why are we just learning this now?<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xODgyMDAzOS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY2MjUyNDMyMH0.Zl8GmQ_rJHiL4b7hN0r_YBmgb6_ZqIRvqOVuko2ubpw/img.jpg?width=1245&coordinates=0%2C141%2C0%2C185&height=700" id="87afe" class="rm-shortcode" data-rm-shortcode-id="dd4c0b5088e601d7279cc5eb226f8b7b" data-rm-shortcode-name="rebelmouse-image" />
"Mosaic pattern of the angle of polarization around the L5 point (white dot) of the Earth-Moon system. The five rectangular windows correspond to the imaging telescope with which the patterns of the Kordylewski cloud were measured."
J. Slíz-Balogh<p>The objects, being dust clouds, are very faint and hard to see. While Kordylewski observed them in 1961, other astronomers have looked there and given mixed reports over the following decades. This discouraged many astronomers from joining the search, as study co-author Judit Slíz-Balogh <a href="https://ras.ac.uk/news-and-press/research-highlights/earths-dust-cloud-satellites-confirmed" target="_blank">explained</a>, <em>"The Kordylewski clouds are two of the toughest objects to find, and though they are as close to Earth as the Moon are largely overlooked by researchers in astronomy. It is intriguing to confirm that our planet has dusty pseudo-satellites in orbit alongside our lunar neighbor."</em></p>
Will this have any impact on space travel?<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="c3d797fff5430c64afcb5a49bddc3616"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/Ou8N3v9SFPE?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>Lagrange points have been put forward as excellent locations for a space station or satellites like the <a href="https://jwst.nasa.gov/about.html" target="_blank">James Webb Telescope</a> to be put into orbit, as they would require little fuel to stay in place. Knowing about a massive dust cloud that could damage sensitive equipment already being there could save money and lives in the future. While we only know about the clouds at Lagrange points four and five right now, the study's authors suggest there could be more at the other points.</p><p>While the discovery of a couple of dust clouds might not seem all that impressive, it is the result of a half-century of astronomical and mathematical work and reminds us that wonders are still hidden in our cosmic backyard. While you might never need to worry about these clouds again, there is nothing wrong with looking at the sky with wonder at the strange and fantastic things we can discover. </p>
New cancer-scanning technology reveals a previously unknown detail of human anatomy.
- Scientists using new scanning technology and hunting for prostate tumors get a surprise.
- Behind the nasopharynx is a set of salivary glands that no one knew about.
- Finding the glands may allow for more complication-free radiation therapies.
PSMA PET/CT technology<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="676e611b970c9b516cace0870447b325"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/RHAyoQF09X4?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>PSMA PET/CT is a new combination of <a href="https://www.mayoclinic.org/tests-procedures/pet-scan/about/pac-20385078" target="_blank">PET scans</a> and <a href="https://www.mayoclinic.org/tests-procedures/ct-scan/about/pac-20393675" target="_blank">CT scans</a> that is believed to offer a more reliable means of locating prostate cancer metastasis. A <a href="https://www.cancer.gov/news-events/cancer-currents-blog/2020/prostate-cancer-psma-pet-ct-metastasis" target="_blank" rel="noopener noreferrer">study</a> published last spring suggests it may be the most accurate way to diagnose prostate cancer metastasis than any method previously available.</p><p>Prior to PSMA PET/CT, the primary way to look for metastatic prostate cancer was to image the body using x-ray-based CT scans and to perform bone scans, since bone is where prostate cancer often spreads. CT scans, however, often miss small tumors, and bone scans can generate false positives as a result of other damage or abnormalities that have nothing to do with prostate cancer.</p><p>PSMA PET/CT scans track the travels of an intravenously administered radioactive glucose tracer throughout the body. For hunting down prostate cancer, this tracer contains a molecule that binds to the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1472940/" target="_blank">PSMA</a> protein that's present in large amounts in prostate tumors. The molecule is linked to a radioisotope, <a href="https://netrf.org/2018/11/13/gallium-68-scan-for-neuroendocrine-tumors/" target="_blank" rel="noopener noreferrer">gallium-68</a> (Ga-68).</p><p>In last spring's research, PSAM PET/CT was shown to be 27 percent more accurate than previous methods at finding metastases (92 percent accuracy as opposed to 65 percent). In addition, it was found to be much less likely to produce false positives, and it was particularly good at detecting tumors far removed from the prostate.</p>
A good kind of avoidance behavior<p>"Radiation therapy can damage the salivary glands," says Vogel, "which may lead to complications. Patients may have trouble eating, swallowing, or speaking, which can be a real burden."</p><p>The researchers looked back through the cases of 723 patients who had undergone radiation treatment, interested in seeing if inadvertent radiation of the tubarial glands was associated with the complications experienced by the patients. It turned out that this <em>was</em> the case: In cases where more radiation had been delivered to this area, patients did indeed report more in the way of complications of the type one would expect when salivary glands are radiated.</p><p>Now that we know the tubarial salivary glands exist, therapists can stay out of their way. Vogel says, "For most patients, it should technically be possible to avoid delivering radiation to this newly discovered location of the salivary gland system in the same way we try to spare known glands."</p><p>He's hopeful that that things may be about to get at least a bit better for cancer patients: "Our next step is to find out how we can best spare these new glands and in which patients. If we can do this, patients may experience less side effects which will benefit their overall quality of life after treatment."</p>
A new survey found that 27 percent of millennials are saving more money due to the pandemic, but most can't stay within their budgets.