Genetics

Will Storr, for Mosaic Science, wades into the world of neuroplasticity and explores to what extent our brains are capable of changing through adulthood. He asks if the tendency to overemphasize the findings of epigenetics and neuroplasticity isn’t tied to our cultural belief that individuals are totally free to create themselves and pursue the American dream.

"We found that the anatomy of the chimpanzee brain is more strongly controlled by genes than that of human brains, suggesting that the human brain is extensively shaped by its environment no matter its genetics," said Aida Gómez-Robles, postdoctoral scientist at the GW Center for the Advanced Study of Human Paleobiology and lead author on the paper. "So while genetics determined human and chimpanzee brain size, it isn't as much of a factor for human cerebral organization as it is for chimpanzees."

MIA contributor, Peter Kinderman, from the University of Liverpool, is teaching a free online course that explores new perspectives on the “nature vs nurture” debate, and how we are affected by life experiences.

“My vegetable beds have even buoyed me through more acute stressors, such as my medical internship, my daughter’s departure for college, and a loved one’s cancer treatment,” writes Dr. Daphne Miller. Now neuroscientists are attempting to study the antidepressant effects of soil microbes in hopes of unlocking the secrets of a powerful mood enhancer.

In his reaction to Dr. Makari’s Opinion piece in the ‘Times, entitled Psychiatry’s Mind-Brain Problem, Dr. Nardo articulates why the legacy of NIMH director Thomas Insel is so dangerous. “He may have kept the researchers from spinning off and following some idiosyncratic path, but he did it by forcing them to follow his own idiosyncratic path.”

In the Boston Globe, Sarah Schweitzer tells the story of a young boy brutally abused by his parents then given to his grandparents who struggled with extreme poverty and homelessness. “Researchers now understood that trauma could alter the chemistry of developing brains and disrupt the systems that help a person handle stress, propelling a perpetual state of high alert. The consequences could be lifelong. As an adult, he’d be more likely to suffer anxiety and depression and heart disease and stroke. His ability to hold a job, manage money, and make good decisions could be compromised. And there was evidence, controversial but mounting, that he could pass on these traits to his children.”

Researchers recently completed a first of its kind, large-scale international survey of attitudes about mental health and they were surprised by the results. According to their analysis published in this month’s issue of the Journal of Affective Disorders, people in developed countries, like the United States, are more likely to assume that ‘mental illnesses’ are similar to physical illnesses and biological or genetic in origin, but they are also much less likely to think that individuals can overcome these challenges and recover

The National Institute of Mental Health (NIMH) is increasingly shifting its research emphasis toward attempting to uncover biomarkers for “mental diseases,” which may have dramatic consequences for research and training in clinical psychology. In an article to be published in next month’s Professional Psychology: Research and Practice, Marvin Goldfried outlines how the shift in funding priorities for psychological research is tied to the needs of pharmaceutical companies and the biological model in psychiatry.

Nature magazine reports on recent discoveries by neuroscientists that microbes that live in the intestinal track may have an influence on brain development and behavior. “Researchers have drawn links between gastrointestinal pathology and psychiatric neurological conditions such as anxiety, depression, autism, schizophrenia and neurodegenerative disorders—but they are just links.”

Human behavioral genetics and its allied field of psychiatric genetics are in trouble, as unfulfilled gene discovery expectations during the “euphoria of the 1980s” have continued to the present day, leading to researchers’ “nonreplication curse” dysphoria of the 2010s. In my recent book The Trouble with Twin Studies: A Reassessment of Twin Research in the Social and Behavioral Sciences, I presented a detailed argument that genetic interpretations of the common “classical twin method” finding that reared-together MZ twin pairs resemble each other more (correlate higher) for behavioral characteristics than do reared-together same-sex DZ twin pairs are invalid because, among other reasons, the twin method’s crucial MZ-DZ “equal environment assumption” (EEA) is false.

“Genetic explanations for violent crimes may encourage jurors to support an insanity defense, but jurors may also believe the defendant is a persistent threat who will commit more crimes in the future,” Science Daily reports. A study on over 600 participants found that when people read a genetic explanation for a violent murder they attributed less blame to the defendant but recommended a longer sentence.

While a great deal of the excitement about advances in psychological treatments comes from the potential for research in neuroscience to unlock the secrets of the brain, many mental health experts would like to temper this enthusiasm. A special issue of the Behavior Therapist released this month calls into question the predominant conception of mental illnesses as brain disorders.

Dr. Vincent Felitti details the connection between childhood trauma and negative mental health outcomes in adulthood in a powerful video.

Even thought current mental health treatments are “suboptimal,” there is a lack of attention paid to the preventative effects of diet and nutrition. Recent studies suggests that nutritional changes can influence the risk for mental health issues and that nutritional supplements, called nutraceuticals, can be prescribed for existing conditions.

With the explosion of genetic testing and the emerging field of pharmacogenetics, patients can now take a DNA test and receive psychiatric drug recommendations customized to fit their genetic makeup. In an editorial for the latest issue of the Journal of Nervous and Mental Disease, Columbia University Psychiatrist Robert Klitzman warns that clinicians need to be aware of the limitations of these genetic tests being marketed to them.

“Stress damages the integrity of the hippocampus, which is the part of the brain that deals with memory and emotions,” Thor Benson writes for Salon. “Hormones like Cortisol and other biological reactions created by stress essentially disrupt the balance of how much white and grey matter the brain is creating, which affects how the brain operates.”

There seems to be no end to illogical and even comical “findings” from MZ-DZ twin method comparisons, where the original twin researchers argue that the greater behavioral resemblance of reared-together MZ (monozygotic, identical) versus same-sex DZ (dizygotic, fraternal) twin pairs demonstrates the “heritability” of the behavioral characteristic in question. Among these we find a twin study whose authors concluded in favor of a genetic basis for being a “born again Christian” (65% heritability), another that found important genetic influences on tea and coffee drinking preferences, and still another that found that the heritability of “loneliness in adults” is 48%.

-John Horgan criticizes psychiatrist Richard Friedman's effusive portrayal of a study that allegedly identified the "feel-good" gene in humans.

-How are learnings in epigenetics re-defining human bodies and brains, and what does that mean for our ideas about "normalcy"?

In a 1992 essay, British psychiatric genetic researcher Michael Owen wondered whether schizophrenia molecular genetic research would become the “graveyard of molecular geneticists.”1 Owen predicted that if major schizophrenia genes existed, they would be found within five years of that date. He was optimistic, believing that “talk of graveyards is premature.”2 Owen now believes that genes for schizophrenia and other disorders have been found, and was subsequently knighted for his work. Despite massively improved technology, however, decades of molecular genetic gene finding attempts have failed to provide consistently replicated evidence of specific genes that play a role in causing the major psychiatric disorders.

The psychiatric genetics literature contains few references to specific environmental factors that cause psychiatric disorders, and while researchers acknowledge a role for these factors, they usually claim that environmental causes are mysterious or unknown. As a leading group of psychiatric genetic researchers recently put it, while claiming that schizophrenia “has a substantial genetic contribution,” the “underlying causes and pathogenesis of the disorder remains unknown.” But research suggests otherwise.

Other studies have shown that abstracts and press releases often mislead journalists about the significance of findings in behavioral genetics; but a new study...

Writing in the Genetic Literacy Project, David Warmflash discusses a recent study that identified two genes "associated with violent crime." Even though people with...

Twin studies supply the most frequently cited evidence in favor of important genetic influences on human behavioral differences. In an extremely small yet influential handful of studies, twin pairs were said to have been reared apart in different families. Twin researchers and others view this occurrence as the ultimate test of the relative influences of nature (genes) and nurture (environment). According to this view all behavioral resemblance between reared-apart MZ twin pairs (known as “MZA” pairs) must be the result of their 100% genetic similarity, because such pairs share no environmental similarity. But, far from being separated at birth and reared apart in randomly selected homes representing the full range of potential behavior-influencing environments, and meeting each other for the first time when studied, most MZA pairs were only partially reared apart, and grew up in similar cultural and socioeconomic environments at the same time.

In Discover, Neuroskeptic discusses a new study that "could undermine the concept of ‘endophenotypes’ – and thus derail one of the most promising lines...