[Update: adds mention of Time magazine story.]
A team of researchers who analyzed genetic data on 33,000 people with mental illness and 28,000 controls discovered that the five most common mental illnesses–depression, autism, attention-deficit disorder, schizophrenia, and bipolar disorder–share some of the same genetic abnormalities.
The finding, while it does not immediately lead to better treatment for any of these severe illnesses, does move researchers closer to understanding their causes. As Lauran Neergaard wrote for the AP:
"These disorders that we thought of as quite different may not have such sharp boundaries," said Dr. Jordan Smoller of Massachusetts General Hospital, one of the lead researchers for the international study appearing in The Lancet.
That has implications for learning how to diagnose mental illnesses with the same precision that physical illnesses are diagnosed, said Dr. Bruce Cuthbert of the National Institute on Mental Health, which funded the research.
Neergaard's story would have had a little more heft if researchers unconnected with the study shared the enthusiasm of these researchers, who were involved. But if she talked to them, she doesn't include their comments in the version I read.
Maggie Fox of NBC News got comment from Ken Duckworth, medical director of the National Alliance on Mental Illness, a patient advocacy group, who told her that "every psychiatrist knows of patients whose symptoms don't clearly meet the definition of any one disease." Still, he didn't comment directly on the study or whether its methodology was sound.
Gina Kolata at The New York Times rounds up comment form others and gets to a level of detail that much of the other coverage missed. She quotes one researcher not involved in the study who says "it was significant that the researchers had found common genetic factors that pointed to a specific signaling system." That's a little mysterious until half a dozen paragraphs later when she explains that some of the genetic signposts found to be common in multiple mental illnesses involved calcium channels, which are involved in communication within the brain. She also reports that a very small trial of drugs called calcium-channel blockers that are already on the market suggests they might have some value in treating bipolar disorder.
Carolyn Y. Johnson at The Boston Globe elicits an interesting hypothetical from one researcher, who tells Johnson that "there may be some very common genetic variants that, let’s say hypothetically, very early on affect very early brain development. . . . Then, maybe environment, or interactions with other genes” can affect which disease appears.
The most comprehensive story I found was by Maia Szalavitz at Time magazine. She hits the question of the soundness of the study right on the head (a researcher not connected with it says "this is a really well done study…"), and she nabs Thomas Insel, director of the National Institute of Mental Health, for some discussion of the study and its implications. She quotes Insel and another researcher who tell her that the genetic variants identified might raise the risk of developing the illnesses by only a small amount–perhaps 10%. But the findings point the way to a better understanding of the biology.
I'd like to see somebody pick this up for a longer takeout looking at the implications and the directions for future research; it's an important story. The study's abstract is here.