Psychiatric Diagnosis and Genetics

An interesting piece by Vaughan Bell of Mind Hacks. He notes that recent studies in medical genetics tend to undermine the foundations of some psychiatric diagnoses. At Mind Hacks he summarizes as follows:

The “mental illness is a genetic brain disease” folks find that their evidence of choice – molecular genetics – has undermined the validity of individual diagnoses, while the “mental illness is socially constructed” folks find that the best evidence for their claims comes from neurobiology studies.

And here’s a snippet from the Observer piece he wrote, well worth a read:

This new realisation rests on evidence that genetic factors initially associated with, for example, schizophrenia have now been recognised as equally important in raising the risk for several other problems including epilepsy, attention deficit disorder, autism and learning disability.

If you speak the language of science, there’s also a link to a British Journal of Psychiatry review article on the topic:

There is accumulating evidence for shared genetic as well as environmental risk between intellectual disability and other conditions with a neurodevelopmental basis such as autism, attention-deficit hyperactivity disorder, epilepsy and schizophrenia. These can be conceived as lying along a continuum of genetically and environmentally induced neurodevelopmental causality.

As usual, not suggesting diseases such as schizophrenia don’t exist — but our understanding of their causes is far from complete. And of course, DSM-V (Diagnostic and Statistical Manual of Mental Disorders) is slated to come out this May 2013.

 

 

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Reassessing Split-Brain Mythology

Based on a lecture by psychiatrist Iain McGilchrist, author of The Master and His Emissary: The Divided Brain and the Making of the Western World, this RSA video is a real treat. It takes a balanced, thoughtful, nuanced look at the idea that the left and right parts of the brain do in fact have different functions, even if those differences have been over done in popular conception. His opening salvo will reassure the skeptics:

The division of the brain is something neuroscientists don’t like to talk about anymore. It enjoyed a sort of popularity in the 60s and 70s after the first split-brain operations, and it led to a sort of popularization which has since been proved to be entirely false. It’s not true that one part of the brain does reason and the other does emotion, both are profoundly involved in both. It’s not true that language resides only in the left hemisphere. It doesn’t. Important aspects are in the right. It’s not true that visual imagery is only in the right hemisphere, lots of it is in the left. And so, in a sort of fit of despair people have given up talking about it, but the problem won’t really go away. Because this organ, which is all about making connection is profoundly divided. It’s there inside all of us, and it’s got more divided over the course of human evolution.

Paradoxically, McGilchrist then goes on to a detailed assessment of the different functions of the left v. right brain — keeping in mind all the while, that this is a schematic assessment with all kinds of exceptions and qualifications.

Typical of such schemes, he points out that the right brain seems dedicated to sustained, broad, open, vigilant alertness, to connection with others, while the left tends to focus narrowly, sharply, attends to detail, with a tendency to focus on already known, factual information. Such schematic functions seem to apply to animals as well as to humans. It seems that McGilchrist’s view is the right brain has been given short shrift. He notes: “The intuitive mind is a sacred gift and the rational mind is a faithful servant. We have created a society that honors the servant, but has forgotten the gift.”

Less typically of such schemes, he notes the important of the frontal lobes, and how they make humans different from other animals. The purpose of the frontal lobes is

to inhibit the rest of the brain, to stop the immediate happening, so standing back in time and space from the immediacy of experience. And that enables us to do two things. It enables us to do what neuroscientists are always telling us we’re very good at which is outwitting the other party, being Machiavellian. And that’s interesting to me because that’s absolutely right. We can read other people’s minds and intentions and if we so want to we can deceive them. But the bit that’s always curiously left out here is that it also enables us to empathize for the first time. Because there’s a sort of necessary distance from the world. If you’re right up against it you just bite. But if you can stand back and see that other individual is an individual like me who might have interests and values and feelings like mine then you can make a bond.

So there you have another wrinkle — the important role of the frontal lobe in empathy. The video is accompanied by some amusing and very well done animation and contains a great deal of interesting food for thought. Highly recommended.

Mapping the Mindful Brain

Very briefly, came upon some fascinating work by Judson Brewer, MD, interviewed here, at Buddhist Geeks. Dr. Brewer, an assistant professor of psychiatry at Yale is studying the effects of meditation on the brain.

The research, utilizing fMRI brain scanning, finds that meditating deactivates the parts of the brain associated with preoccupation with self, called the “default mode network”. Now, if you could limit the activity of the part of the brain that tended to make people unhappy, would you?

We found a clinical signal and went back to study the mechanism to see what’s actually going on. We compared the neural activity of 12 Buddhist meditators to those of novice meditators that we instructed that morning. As I’m sure your listeners are aware, the instructions are simple “pay attention to your breath” but they are maddeningly hard to do. It’s easy to teach someone, but it’s not that easy to change your brain. We had them do three different kinds of meditation and looked for what was similar among all three.

The researchers found that not only is there a common neurological association to meditation, but using fMRI scans to provide real-time feedback with meditators showed that “an active posterior cingulate correllated very highly with self-referential wandering brain activity” and when it was de-activated they were focussed or in a “flow” state.

So, what of it? Well, not long ago another study, done by Matthew Killingsworth, looked at the effect of the wandering mind. They concluded that about half the time we are thinking about ourselves, and when doing so we are generally unhappy. (Here’s a write-up of that research in Science Daily.)

So could you increase your odds of happiness by taking up a mindfulness practice — by taking that preoccupied self “off-line”, so to speak? There’s lots more research to be done, but it seems to point in that direction. One interesting thing about Brewer’s work, is his team is providing real-time feedback to meditators so that they are able to learn to meditate more efficiently. They had people who learned to meditate, whose meditation looked like those of longtime practitioners, within 9 minutes. (I’m not suggesting that this is a fast-track to learning to meditate like a long-time practitioner, but it does seem to make the learning much more efficient.)

You can also read an article about Brewer’s research at Yale Scientific.

Neurons That Fire Together, Wire Together

He’s Got Google’s Ear. Who gets to speak to an audience at Google? Well, this guy did. He’s Rick Hanson, Ph.D., a neuropsychologist, who spoke on the Google campus a little over two years ago. He is one of the guys recruited by Chade Meng-Tan to speak to the search engine’s employees on the topic of mindfulness, and how it might be beneficial to them. He is also the author of Buddha’s Brain: The Practical Neuroscience of Happiness, Love, and Wisdom.

Three Goal-Directed Systems of the Brain. Hanson posits three goal-directed systems in the brain. The avoidance system (the example of sticks v. carrots), the approach system (which seeks opportunities, rewards, pleasures) and finally, the attachment system (which seeks social proximity, bonding, feelings of closeness). He goes on to map these systems and their associations with various parts of the brain and neurobiological processes — of the attachment system he notes it is part of our “mammalian heritage.” Bonding is a very important part of our survival.

The Negativity Bias of The Brain. Dr. Hanson makes a point regarding what he calls the negative bias of the brain. What does that mean? Well, in a nutshell, we’ve evolved to avoid danger. Think of it this way — which has a higher cost, a) not noticing the tiger in the bushes or b) thinking there is a tiger in the bushes, when there is none? Though being hypervigilant is annoying and in some sense a waste of time, the cost of not noticing the tiger in the bushes is so astronomically higher that we are naturally evolved to be on alert to risks and dangers. This is what Dr. Hanson calls the brain’s innate negativity. He says, “sticks are more salient than carrots” — meaning we are more geared to being alert for threats than seeking reward. That doesn’t mean that there aren’t strong drives for seeking reward — it’s just that removing threat is higher up on the hierarchy. Once we assess risks to be minimal, reward seeking comes to the fore. He adds, “the brain is like velcro for negative experiences, teflon for positive.”

Negativity Bias and Stress. But this tendency to weigh negative input more heavily can be problematic. We’re pretty much adapted to life 50,000 years ago, perhaps more so than as much as for life today. The avoidance system, perfectly tuned to avoiding threat from neighboring tribes and potential predators, can get overloaded by less dire stimulus such as a traffic jam or a bad report card or what have you. And that avoidance system activates the sympathetic nervous system, the fight-0r-flight system. Chronic arousal of this system (as occurs in anxiety and the  hypervigilance associated with trauma) is unhealthy. Chronic stress can lead to a cascade of health events — it weakens the immune system, inhibits the gastrointestinal system (which in turn reduces nutrient absorption), dysregulates hormones, causes cardiovascular vulnerabilities, and so on.

The Take Home Point. I advise watching the video, if you have the time, because it sketches out in more detail his ideas — but I would say the take home point, if there is one, is that it is possible to shape your brain away from what he calls its negative bias. In other words, focussing, through intention, on the approach and attachment parts of the system. How would that work? Well quite a lot of research seems to suggest, quite robustly, that parts of the brain (particularly the anterior cingulate) used in meditation are the same parts of the brain used to regulate emotion. And sketching the idea out crudely, that through attentive practice, we can essentially train our brain to cultivate positive sensations to calm down the fight-or-flight system. Over time, this can actually strengthen the system that regulates strong, primitive emotions. (Daniel Siegel, MD, has followed and participated in this research quite closely.) Check out the video. It’s worth a look.

Some Left-Brain Right-Brain Nonsense

“Left brain/ right brain nonsense in a Mercedez-Benz ad” runs the caption at Neuroimages where this image resides. Why nonsense? Well, I expect the writer felt that the whole left-brain/right-brain dichotomy is a bit overdone, a gross simplification. I would agree. Still, it’s a nice image and reflects what has increasingly become the popular conception of brain function. It’s a useful schematic. But the real truth about the brain is that

  1. it is fantastically complicated and
  2. it is capable of regenerating and repurposing itself

Yes, repurposing itself. The brain is able to reassign functions from one part of the brain to another, within certain limits, of course. Dan Siegel, MD, has done some amazing writing on the various functions of the brain, in part making use of the left-right schematic. He also focuses on “neuroplasticity” that is, very briefly, the ability of the brain’s neurons to grow and adapt according to need. It’s work that has exciting implications for psychotherapy. I’ll be posting more about Dr. Siegel’s work in the not-too-distant future.

Body Position Affects Memory of Events

Fascinating piece at Cognitive Daily on headlined topic, from a 2007 study. One idea that occurs immediately, is that this idea lends credence to treatments for PTSD that involve physical movements, even re-dramatizing the event. Here’s an excerpt:

A new study adds an unexpected method to the list of ways to spur memories about our past: body position. That’s right: just holding your body in the right position means you’ll have faster, more accurate access to certain memories. If you stand as if holding a golf club, you’re quicker to remember an event that happened while you were golfing than if you position your body in a non-golfing pose.

Where Does Brain Become Mind?

Or is there a difference? This remains a heated discussion in cognitive sciences, neuroscience, philosophy. No answer in sight really. But here’s a snapshot of the complexity of your brain. Taken from Daniel Carlat’s piece in Wired:

A typical brain contains 100 billion neurons, each of which makes electrical connections, or synapses, with up to 10,000 other neurons. That means a quadrillion synapses to keep track of at any given time — about the number of people on 150,000 Earths. Somehow, in the midst of this frenetic electrical activity, something called “mind” emerges.