For decades, scientists have been making claims about the genetic roots of mental illness, ranging from schizophrenia and depression, to bipolar disorder and attention deficit disorder (ADHD). And for decades, they’ve largely been chasing ghosts.
Eric Kandel, writing for Newsweek, makes the at-least-annual appeal that scientists are making “certain advances in genetics” which give “us new reasons for optimism” in understanding the biological basis for mental illness. As someone who’s been tracking the progress of such genetic advances over the past two decades, I have to say, I remain squarely skeptical.
It doesn’t help that Kandel’s own arguments are exercises in circular logic:
One major advance has been the discovery that there is much more variability in the genome than had been anticipated, and that this takes the form of copy number variation (CNV). These are duplications or deletions of segments of a chromosome, often involving several or tens of genes, that enhance or depress the actions of specific genes. A well-known example of a CNV is the extra copy of chromosome 21 resulting in Down syndrome. It has recently been discovered that this type of variation is extremely common in everyone’s genome.
If there’s “much more variability in the genome,” guess what? That means finding specific meaningful, predictable variations is all the more challenging. If the extra copy of chromosome 21 is “extremely common,” how come Down syndrome isn’t so much more common?
We’ve highlighted previously altered genes that may increase the risk of schizophrenia, for example. But not a year goes by where more such research highlights other genes or other gene variations. I mean, we’ve been talking about this for years. What’s changed recently?
Nothing. If anything, new research shows just how complicated gene research is. If hundreds of gene variations could be indicted in a “simple,” less-serious mental disorder like attention-deficit disorder, imagine the complexity of more debilitating disorders like depression or bipolar disorder.
Kandel also makes this claim you’ve probably heard before:
Scientists are also making progress in finding the biological markers for depression, anxiety, and obsessive-compulsive neurosis. Markers are essential to understanding the anatomical basis of mental disorders, diagnosing them objectively, and following their response to treatment, as well as perhaps preventing psychosis in those at high risk.
Progress? Well, if you call understanding how extraordinarily complex the human genome is, compared to what we thought it was 10 years ago, yeah, I guess you could call that “progress.” But honestly, researchers are not significantly closer to finding genetic markers for depression, anxiety and OCD than they were a decade ago. Think of our understanding of brain disorders and genetics similar to that of unpeeling an onion. The size of a giant watermelon. Or the moon.
But the strangest point made by Kandel is that the effectiveness of psychotherapy is now “proven” because of brain imaging studies which have been called into question:
The most convincing scientific progress in psychiatry in the past decade has had little to do with genomics. It is the rigorous, scientific verification that certain forms of psychotherapy are effective. […] Insofar as psychotherapy works and produces stable, learned changes in behavior, it can cause stable anatomical changes in the brain. We are now beginning to measure such changes with brain imaging.
Who cares? We don’t need brain imaging to understand that psychotherapy works. I guess all those decades of psychology research showing the effectiveness of psychotherapy were for naught until we had the sheer magic of brain imaging.
While I believe understanding human genetics and the neurological basis of mental disorders is important, invaluable work, I think articles like Kandel’s sort of miss the point. This work is slow and arduous, and for every one step forward, we take two steps back. Indeed, we are making progress, but it is not progress one can easily track or summarize in a mainstream news article of this nature.
In the treatment of mental disorders, we have plenty of approaches that work just as well as (and, in fact, work better than) any medical treatment for a medical disease. (Honestly, Kandel should look at the research behind the vast majority of surgical procedures to see the lack of rigorous scientific data that he’s demanding for mental illnesses.)
Genetics may one day hold some sort of key to our understanding of mental disorders. But that’s a line that’s been repeated hundreds of times over the past two decades, and one that seems no truer today than it did in 1989.
Read the full entry: A Biology of Mind
11 comments
I think it’s likely in conditions like schizophrenia, ADHD and bipolar that there are genetics invlolved, but I also think many forms of depression are certainly caused in large by events occuring throughout one’s life – especially when we are young but not limited to that time.
Science today has changed, I hope you used the right way, because there are medications such as vicodin, oxycodone, Lortab, etc, are anxiolytic and although much help to soothe the pain, can be double-edged weapon to control pain, so indicate in findrxonline to be confident that this discovery is beneficial to all.
Dear Dr Grohol —
I read today’s feature on Eric Kandel with interest as he is one of the panelists in “Minds on the Edge,” our upcoming PBS special (October 09)
Would you be interested in receiving an advance copy of the program for review?
I believe we are already following one another on Twitter, but you can also check us out on Facebook (mind on the edge)
Thanks & all best,
Kristin Fellows
“If the extra copy of chromosome 21 is ‘extremely common, how come Down syndrome isn’t so much more common?”
The passage you quote doesn’t say that an extra copy of chromosome 21 itself is extremely common, but that that type of variation is extremely common. I read that as meaning that an extra copy of any chromosome, not specifically the Downs-related chromosome 21, is common, which doesn’t sound unreasonable. I’m with you that the genetic origins of mental illness are likely to stay pretty elusive for a while, but I think that’s largely because the definitions of mental illnesses are so vague and subjective. Susceptibility to, say, repiratory trouble, almost certainly also has genetic roots, but some lung problems are caused by colds, some by asthma, some by cystic fibrosis, some by smoking, etc., and looking for a single “bad lung gene” or a “chronic coughing gene” would for the most part yield pretty poor results.
The thing to keep in mind is that genetics is often just a predisposition to a problem, not a 100% indicator that something will develop. It’s good that some scientists are trying to isolate genes. It’s also good that other scientists are learning how environmental factors activate and deactivate certain genes; especially interesting is the possibility (as with some research on autism and fever) that genes that get switched in one direction can reverse direction during the lifespan. Intake of vitamins (especially vitamin D, the only vitamin whose creation is primarily endogenous) and nutrients, environmental toxins, and psychosocial stress all interact with our genes in ways that are not yet clear. It seems that new branches of science should be created that focus on the connections between disparate research and theories. There seems to be way too much compartmentalization and specialization where this type of research is concerned.
That’s really funny — you questioning Eric Kandel’s logic!
People who don’t accept the genetic evidence we already have for some psychiatric illnesses — and the strong epigenetics for many more — need to go back to school so they can understand it. Either that or join the Flat Earth club.
There was going to be magic and we were told the magic was near. ” ‘NAMI takes seriously the statement of Dr.Thomas Insel [in 2003], director of the National Institute for Mental Health (NIMH) that with the right investments, scientists are within reach of finding a cure for schizophrenia in the next ten years,’ said NAMI national executive director Richard C. Birkel, PhD.” Newspapers regularly heralded one genetic discovery after another and the discoveries turned out too often to be less then originally represented.
In the interim services and supports in the community lagged far behind an ever growing need. One can hope for magic but one should never predicate current efforts and plan future actions based upon it.