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Are mental health disorders ever purely biological?
Two anthropologists question the chemical imbalance theory of mental health disorders.
- Two physical anthropologists argue that you cannot pin most mental health disorders on brain chemistry alone.
- As antidepressants will soon be a $16B industry, the chemical imbalance theory suits business interests better than health interests.
- An etiology of depression should include behavioral observation, cross-population comparisons, cultural transmission, and evolutionary theory.
Twentieth-century science was supposed to change everything. Indeed, thanks to vaccinations, antibiotics, and improved sanitation, humans thrived like never before. Yet in that mix was thrown pharmacological treatments for mental health disorders. On that front, little progress has been made.
It can be argued—it is being argued, in a new paper in American Journal of Physical Anthropology—that we're regressing in our fight against mental health problems. As Kristen Syme, a PhD student in Evolutionary Anthropology, and Washington State University anthropology professor Edward Hagen argue, psychopharmacological treatments are increasing alongside mental health disorder diagnoses. If the former worked, the latter would decrease.
There are numerous problems with the current psychiatric model. Journalist Robert Whitaker has laid out the case that antidepressants, antipsychotics, and other pharmacological interventions are the real culprit behind chemical imbalances in the brain—a psychiatric talking point that's been challenged for over a half-century. Patients suffering from minor anxiety and depression are placed on ineffective drugs, often being placed on a cocktail of pills. With many consumer advocacy groups being funded by pharmaceutical companies, we've reached a tipping point in mental health protocols.
As Syme and Hagan write, consumer advocacy groups are not the only compromised organizations. One review of 397 clinical trials discovered 47 percent of these studies reported at least one conflict of interest. As Whitaker has written about before, when pharmaceutical companies don't like the results of their trials, they're scrapped until more suitable results are recorded.
Humans proliferated as never before during the last century, yet technological innovation does not always equate to better outcomes. We live by a perpetual illusion of progress. Severing ties with nature has had profound consequences on our health. This drives to the heart of Syme and Hagan's paper: brain chemistry is heavily influenced by society. Sure, some people are born with genetic-based developmental dysfunctions. This doesn't account for increasing numbers of people on Zoloft and Xanax and dozens of other medications today.
EarthRise 91: Do antidepressants create more mental illness than they cure? (with Robert Whitaker)
Physical anthropology and evolutionary biology are essential fields of study when contemplating all facets of health. Historical perspective is important. The authors point to a previous battle: in 1900, roughly half of all deaths in the U.S. were attributed to infectious diseases. A century later, the number of deaths due to such diseases was negligible.
That's because the etiologies of a number of infectious diseases were discovered thanks to germ theory. There has never been a holistic etiology of anxiety or depression, however. Psychiatrists, in coordination with pharmaceutical companies, exploited that fact by creating and marketing a singular etiology—the chemical imbalance theory—and selling the world on pharmacology.
Think about the basic framework of this proposition: an animal that has evolved for millions of years, roughly 350,000 in the present form, experiences its greatest century to date in terms of population expansion, while simultaneously billions of our brains are suddenly chemically compromised. This narrative boggles the mind, yet it's exactly what's being sold by psychiatrists and medical doctors around the world.
As the authors write, the chemical imbalance theory, first widely discussed in the late forties, became part of a public health campaign designed to destigmatize mental health issues in the aughts. In reality, the campaign accomplished the opposite.
"First, a systematic review found that an endorsement of biogenetic causes of mental disorders does not reduce stigma and, in fact, might even increase stigmatizing attitudes among mental health professionals and the mentally ill themselves. Second, there is little evidence that psychopharmaceuticals correct specific chemical imbalances or neurobiological deficits."
While mental health is a broad term with numerous categories, the authors divide disorders into four subsets:
- Disorders which are genetic-based developmental dysfunctions
- Disorders associated with senescence/aging
- Disorders caused by a mismatch between modern and ancestral environments
- Disorders which are adaptive responses to adversity, however undesirable
Photo: Everett Collection / Shutterstock
The first two account for many common diseases, such as dementia, autism, and schizophrenia. The second pair represent disorders that modern psychiatry has exploited. By failing to consider environmental, racial, economic, familial, and societal forces, we've been sold a story that we're broken from birth.
This story serves a purpose: the global antidepressant industry is expected to reach $16B by 2023. Thanks to concerted marketing and lobbying efforts, an uptick in prescriptions coincides with an increasing number of disorders—and increasing numbers of children on these drugs. When one market is exploited, create another.
Pharmacological interventions for Parkinson's, Alzheimer's, and autism might be valuable to patients of these disorders. The problem isn't with drug development, which is a necessary field of research for combating such confounding diseases. As has long been known—since at least the 19th century, though likely much longer—most anxiety and depression alleviates with time, especially when interventions such as proper diet, exercise, and improved economic conditions are put into place. As Syme and Hagan conclude,
"A final group of disorders, such as anxiety, depression, and PTSD, have low heritability, are caused by adversity, and involve symptoms that seem to be adaptive responses to adversity. Because they are relatively common throughout adult life, they account for a substantial fraction of disease burden attributable to mental illness. These might not be disorders at all, however, but instead aversive yet adaptive responses to adversity."
That is, anxiety and depression are largely social problems, not medical disorders. The authors write that it would be unethical to prescribe pain medication for a broken bone without first setting the bone. Why then do psychiatrists and doctors churn out scripts without identifying the source of suffering that brought the patient into the office in the first place?
Though we don't yet have reliable etiologies of most mental health disorders, the authors conclude that they could be within reach. Their discovery relies not on brain chemistry alone, but on epigenetics, behavioral observation, cross-population comparisons, cultural transmission, evolutionary theory, and much more.
Humans are complex animals. Perhaps Occam's razor isn't as sharp as we believe.
- If depression isn't caused by a chemical imbalance, how do we treat it? ›
- Think of mental disorders as the mind's 'sticky tendencies' ›
- Depression isn't a chemical imbalance. It's a social problem. We ... ›
"You dream about these kinds of moments when you're a kid," said lead paleontologist David Schmidt.
- The triceratops skull was first discovered in 2019, but was excavated over the summer of 2020.
- It was discovered in the South Dakota Badlands, an area where the Triceratops roamed some 66 million years ago.
- Studying dinosaurs helps scientists better understand the evolution of all life on Earth.
David Schmidt, a geology professor at Westminster College, had just arrived in the South Dakota Badlands in summer 2019 with a group of students for a fossil dig when he received a call from the National Forest Service. A nearby rancher had discovered a strange object poking out of the ground. They wanted Schmidt to take a look.
"One of the very first bones that we saw in the rock was this long cylindrical bone," Schmidt told St. Louis Public Radio. "The first thing that came out of our mouths was, 'That kind of looks like the horn of a triceratops.'"
After authorities gave the go-ahead, Schmidt and a small group of students returned this summer and spent nearly every day of June and July excavating the skull.
Credit: David Schmidt / Westminster College
"We had to be really careful," Schmidt told St. Louis Public Radio. "We couldn't disturb anything at all, because at that point, it was under law enforcement investigation. They were telling us, 'Don't even make footprints,' and I was thinking, 'How are we supposed to do that?'"
Another difficulty was the mammoth size of the skull: about 7 feet long and more than 3,000 pounds. (For context, the largest triceratops skull ever unearthed was about 8.2 feet long.) The skull of Schmidt's dinosaur was likely a Triceratops prorsus, one of two species of triceratops that roamed what's now North America about 66 million years ago.
Credit: David Schmidt / Westminster College
The triceratops was an herbivore, but it was also a favorite meal of the Tyrannosaurus rex. That probably explains why the Dakotas contain many scattered triceratops bone fragments, and, less commonly, complete bones and skulls. In summer 2019, for example, a separate team on a dig in North Dakota made headlines after unearthing a complete triceratops skull that measured five feet in length.
Michael Kjelland, a biology professor who participated in that excavation, said digging up the dinosaur was like completing a "multi-piece, 3-D jigsaw puzzle" that required "engineering that rivaled SpaceX," he jokingly told the New York Times.
Morrison Formation in Colorado
James St. John via Flickr
The Badlands aren't the only spot in North America where paleontologists have found dinosaurs. In the 1870s, Colorado and Wyoming became the first sites of dinosaur discoveries in the U.S., ushering in an era of public fascination with the prehistoric creatures — and a competitive rush to unearth them.
Since, dinosaur bones have been found in 35 states. One of the most fruitful locations for paleontologists has been the Morrison formation, a sequence of Upper Jurassic sedimentary rock that stretches under the Western part of the country. Discovered here were species like Camarasaurus, Diplodocus, Apatosaurus, Stegosaurus, and Allosaurus, to name a few.
|Credit: Nobu Tamura/Wikimedia Commons|
As for "Shady" (the nickname of the South Dakota triceratops), Schmidt and his team have safely transported it to the Westminster campus. They hope to raise funds for restoration, and to return to South Dakota in search of more bones that once belonged to the triceratops.
Studying dinosaurs helps scientists gain a more complete understanding of our evolution, illuminating a through-line that extends from "deep time" to present day. For scientists like Schmidt, there's also the simple joy of coming to face-to-face with a lost world.
"You dream about these kinds of moments when you're a kid," Schmidt told St. Louis Public Radio. "You don't ever think that these things will ever happen."
Are "humanized" pigs the future of medical research?
The U.S. Food and Drug Administration requires all new medicines to be tested in animals before use in people. Pigs make better medical research subjects than mice, because they are closer to humans in size, physiology and genetic makeup.
In recent years, our team at Iowa State University has found a way to make pigs an even closer stand-in for humans. We have successfully transferred components of the human immune system into pigs that lack a functional immune system. This breakthrough has the potential to accelerate medical research in many areas, including virus and vaccine research, as well as cancer and stem cell therapeutics.
Existing biomedical models
Severe Combined Immunodeficiency, or SCID, is a genetic condition that causes impaired development of the immune system. People can develop SCID, as dramatized in the 1976 movie “The Boy in the Plastic Bubble." Other animals can develop SCID, too, including mice.
Researchers in the 1980s recognized that SCID mice could be implanted with human immune cells for further study. Such mice are called “humanized" mice and have been optimized over the past 30 years to study many questions relevant to human health.
Mice are the most commonly used animal in biomedical research, but results from mice often do not translate well to human responses, thanks to differences in metabolism, size and divergent cell functions compared with people.
Nonhuman primates are also used for medical research and are certainly closer stand-ins for humans. But using them for this purpose raises numerous ethical considerations. With these concerns in mind, the National Institutes of Health retired most of its chimpanzees from biomedical research in 2013.
Alternative animal models are in demand.
Swine are a viable option for medical research because of their similarities to humans. And with their widespread commercial use, pigs are met with fewer ethical dilemmas than primates. Upwards of 100 million hogs are slaughtered each year for food in the U.S.
In 2012, groups at Iowa State University and Kansas State University, including Jack Dekkers, an expert in animal breeding and genetics, and Raymond Rowland, a specialist in animal diseases, serendipitously discovered a naturally occurring genetic mutation in pigs that caused SCID. We wondered if we could develop these pigs to create a new biomedical model.
Our group has worked for nearly a decade developing and optimizing SCID pigs for applications in biomedical research. In 2018, we achieved a twofold milestone when working with animal physiologist Jason Ross and his lab. Together we developed a more immunocompromised pig than the original SCID pig – and successfully humanized it, by transferring cultured human immune stem cells into the livers of developing piglets.
During early fetal development, immune cells develop within the liver, providing an opportunity to introduce human cells. We inject human immune stem cells into fetal pig livers using ultrasound imaging as a guide. As the pig fetus develops, the injected human immune stem cells begin to differentiate – or change into other kinds of cells – and spread through the pig's body. Once SCID piglets are born, we can detect human immune cells in their blood, liver, spleen and thymus gland. This humanization is what makes them so valuable for testing new medical treatments.
We have found that human ovarian tumors survive and grow in SCID pigs, giving us an opportunity to study ovarian cancer in a new way. Similarly, because human skin survives on SCID pigs, scientists may be able to develop new treatments for skin burns. Other research possibilities are numerous.
The ultraclean SCID pig biocontainment facility in Ames, Iowa. Adeline Boettcher, CC BY-SA
Pigs in a bubble
Since our pigs lack essential components of their immune system, they are extremely susceptible to infection and require special housing to help reduce exposure to pathogens.
SCID pigs are raised in bubble biocontainment facilities. Positive pressure rooms, which maintain a higher air pressure than the surrounding environment to keep pathogens out, are coupled with highly filtered air and water. All personnel are required to wear full personal protective equipment. We typically have anywhere from two to 15 SCID pigs and breeding animals at a given time. (Our breeding animals do not have SCID, but they are genetic carriers of the mutation, so their offspring may have SCID.)
As with any animal research, ethical considerations are always front and center. All our protocols are approved by Iowa State University's Institutional Animal Care and Use Committee and are in accordance with The National Institutes of Health's Guide for the Care and Use of Laboratory Animals.
Every day, twice a day, our pigs are checked by expert caretakers who monitor their health status and provide engagement. We have veterinarians on call. If any pigs fall ill, and drug or antibiotic intervention does not improve their condition, the animals are humanely euthanized.
Our goal is to continue optimizing our humanized SCID pigs so they can be more readily available for stem cell therapy testing, as well as research in other areas, including cancer. We hope the development of the SCID pig model will pave the way for advancements in therapeutic testing, with the long-term goal of improving human patient outcomes.
Adeline Boettcher earned her research-based Ph.D. working on the SCID project in 2019.
Satellite imagery can help better predict volcanic eruptions by monitoring changes in surface temperature near volcanoes.
- A recent study used data collected by NASA satellites to conduct a statistical analysis of surface temperatures near volcanoes that erupted from 2002 to 2019.
- The results showed that surface temperatures near volcanoes gradually increased in the months and years prior to eruptions.
- The method was able to detect potential eruptions that were not anticipated by other volcano monitoring methods, such as eruptions in Japan in 2014 and Chile in 2015.
How can modern technology help warn us of impending volcanic eruptions?
One promising answer may lie in satellite imagery. In a recent study published in Nature Geoscience, researchers used infrared data collected by NASA satellites to study the conditions near volcanoes in the months and years before they erupted.
The results revealed a pattern: Prior to eruptions, an unusually large amount of heat had been escaping through soil near volcanoes. This diffusion of subterranean heat — which is a byproduct of "large-scale thermal unrest" — could potentially represent a warning sign of future eruptions.
Conceptual model of large-scale thermal unrestCredit: Girona et al.
For the study, the researchers conducted a statistical analysis of changes in surface temperature near volcanoes, using data collected over 16.5 years by NASA's Terra and Aqua satellites. The results showed that eruptions tended to occur around the time when surface temperatures near the volcanoes peaked.
Eruptions were preceded by "subtle but significant long-term (years), large-scale (tens of square kilometres) increases in their radiant heat flux (up to ~1 °C in median radiant temperature)," the researchers wrote. After eruptions, surface temperatures reliably decreased, though the cool-down period took longer for bigger eruptions.
"Volcanoes can experience thermal unrest for several years before eruption," the researchers wrote. "This thermal unrest is dominated by a large-scale phenomenon operating over extensive areas of volcanic edifices, can be an early indicator of volcanic reactivation, can increase prior to different types of eruption and can be tracked through a statistical analysis of little-processed (that is, radiance or radiant temperature) satellite-based remote sensing data with high temporal resolution."
Temporal variations of target volcanoesCredit: Girona et al.
Although using satellites to monitor thermal unrest wouldn't enable scientists to make hyper-specific eruption predictions (like predicting the exact day), it could significantly improve prediction efforts. Seismologists and volcanologists currently use a range of techniques to forecast eruptions, including monitoring for gas emissions, ground deformation, and changes to nearby water channels, to name a few.
Still, none of these techniques have proven completely reliable, both because of the science and the practical barriers (e.g. funding) standing in the way of large-scale monitoring. In 2014, for example, Japan's Mount Ontake suddenly erupted, killing 63 people. It was the nation's deadliest eruption in nearly a century.
In the study, the researchers found that surface temperatures near Mount Ontake had been increasing in the two years prior to the eruption. To date, no other monitoring method has detected "well-defined" warning signs for the 2014 disaster, the researchers noted.
The researchers hope satellite-based infrared monitoring techniques, combined with existing methods, can improve prediction efforts for volcanic eruptions. Volcanic eruptions have killed about 2,000 people since 2000.
"Our findings can open new horizons to better constrain magma–hydrothermal interaction processes, especially when integrated with other datasets, allowing us to explore the thermal budget of volcanoes and anticipate eruptions that are very difficult to forecast through other geophysical/geochemical methods."