A new study published in The Lancet has linked several of the same genetic mutations to autism, attention deficit hyperactivity disorder, schizophrenia, bipolar disorder and major depression. While no one is surprised about the genetic basis of these disorders or for that matter anything else in this The Biological Century, the Lancet study brings pretty remarkable news for the mental health community. Often there's news about a gene tied to one disorder, not several different diseases or disorders or in this case five of the best-known and one could argue most severe psychiatric disorders. Oh yeah, it's also the largest study ever to look at the genetic bases of psychiatric disorders, a study of over 60,000 subjects worldwide:
The work began in 2007 when a large group of researchers began investigating genetic data generated by studies in 19 countries and including 33,332 people with psychiatric illnesses and 27,888 people free of the illnesses for comparison. The researchers studied scans of people’s DNA, looking for variations in any of several million places along the long stretch of genetic material containing three billion DNA letters. The question: Did people with psychiatric illnesses tend to have a distinctive DNA pattern in any of those locations? 5 Disorders Share Genetic Risk Factors, Study Finds via New York TimesBasically the study team identified 4 locations with genetic mutations. Two of the spots involve genes active in the brain's signaling system. As for the other two, the researchers don't which genes are involved. These spots which involve calcium proteins make a lot of sense to neuroscientists so they don't appear to be just freak significant findings though of course they could be. It's a massive amount of data and who knows how many significance tests were done so it's possible these were freak findings.
Let's say they hold, it's clear we'll have biological markers to better identify these major disorders someday. What does this mean for the fields of psychiatry and psychology? It suggests diagnoses will be made on the basis of not merely behavioral symptoms but biological ones. For better or for worse. Kids will be poked with the needle, perhaps swabbed in the cheek. Who knows how this will impact treatment or for that matter the lives of children and parents around the world. It does suggest the professionals writing the Diagnostic and Statistical Manual will face some serious dilemnas in the future. Arguments over how to define disorders (by behavioral or biological symptoms?) will make the imminent fifth edition, due in May, look decidely less controversial.
Anyhow these results taken with other recent research involving twins and families suggest the same genetic variations may results in different symptoms perhaps based on environmental triggers. Heady stuff. One identical twin with schizophrenia, the other autism.
To temper my breathlessness here, let me add that these genetic processes gone amok involve only a tiny subset of possibly hundreds if not thousands of genes responsible for these disorders. These mutations explain only a very small amount of the risks for exhibiting these disorders. Experts took pains to point this out in the numerous articles on this study though even they seemed slightly impressed and I'm not just talking about the study authors.
Note: I am not mentioning any surprised researchers here. Feel free to voice surprise on this one. Free pass here. Spring break starts tomorrow, I'm feeling benevolent.
What about you, are you surprised? Awe-struck?
Identification of risk loci with shared effects on five major psychiatric disorders: a genome-wide analysis
The Lancet, Early Online Publication, 28 February 2013