I know to some people, saying that bipolar, schizophrenia and depression are genetic is like saying the sky is blue. We know that these illnesses are genetic. It’s obvious. It’s also pretty obvious (to, me, anyway) that bipolar disorder, depression and schizophrenia overlap in some ways. Nonetheless, some people require yet more proof. Well, welcome to some more proof. Bipolar disorder, schizophrenia, depression (and actually autism and alcoholism) are genetic and these illnesses’ genes even overlap. Yes, we bipolars are genetically linked to our brothers and sisters with other psychiatric disorders.
Linking of Bipolar, Schizophrenia, Depression and More
A new paper out called Shared Molecular Neuropathology Across Major Psychiatric Disorders Parallels Polygenic Overlap now provides more proof these five mental illnesses are genetic and, in fact, even genetically linked and have overlapping expressions in the brain.
This doesn’t surprise me in the least. I have felt a certain connection to other mental illnesses forever. I can’t say what full-on psychosis feels like, for example, as I’ve never experienced it; but, I feel like I have an inkling due to my own experiences with bipolar disorder. I’ve always felt (and this is not the first bit of evidence saying it) that bipolar disorder and schizophrenia are linked.
And I like to think it’s obvious that unipolar depression and bipolar disorder exist on a spectrum. Straight, unipolar depression is at one end and bipolar disorder type I is at the other. But, of course, there are kinds in the middle like bipolar II and cyclothymia. (Jim Phelps MD, agrees with me and one of his articles on it is here.)
Now as for the genetic link between bipolar disorder, autism and alcoholism, that’s a new one for me. But just for the record, my father was both an alcoholic and bipolar.
And again, while I don’t have autism, I feel a distinct kinship with those who do. Their experiences are not mine, exactly, but I believe I have had a small taste of what autism is like in my own bipolar experiences.
Showing Genetic Overlap of Bipolar Disorder, Depression and Schizophrenia
How do we know that these overlaps exist (beyond my suspicion that they do), well, neurogenetic science, of course. I highly recommend you take a peek at the article I linked to above if you’re a science-y type of person, but if you’re not, don’t worry, I’ll give you the rundown here.
Michael J. Gandal et al looked at 700 brains, some with each disorder and then 293 matched controls (brains without psychiatric disorders). (FYL, only 17 brains had alcoholism, making that link the weakest, in my opinion.)
These scientists then went on to perform a whole whack of statistical and genetic testing to ensure what they were looking at was only the gene expression overlap for these disorders and not confounding variables. (For details, you’ll have to see the study. In my opinion, they were very thorough but also very hard to understand.)
Moreover, these scientists even accounted for the effects that antipsychotic medication may have on the brain. (They did this by using the brains of primates that were made psychotic and then given antipsychotic medication. [Kind of icky, I know.])
Antipsychotics Effects on Sick Bipolar and Schizophrenic Brains
The fascinating thing the scientists found (as a bit of an aside), was that antipsychotics actually normalized some of these genetic expressions. In other words, antipsychotics do, in fact, work to make a brain function more normally.
Depression, Bipolar and Schizophrenia Genetic Links
In short, what the scientists found was that shared genetic factors underlie this gene expression overlap in bipolar disorder, schizophrenia, depression, autism and alcoholism. They indicate that most of these effects are likely rooted in genetic risk. Note that they do not say that environmental factors do not play a role – in fact, they note the opposite, environmental factors likely contribute to the variation seen in the brains (as not everything to do with the illnesses overlaps in every brain, obviously).
The Effect that Depression, Bipolar and Schizophrenia Genetic Links May Have on Treatment
According to The Washington Post, by using genetics and what is known about the molecules, scientists can look at mental illness in a whole new way, says Daniel Geschwind, a neurogeneticist and leader of the study.
Geschwind also says:
“What we’re seeing is giving us a sense of alterations in the way neurons are signaling to each other. We think some of it is confused activity. That’s the next step, to connect it to the physiology: how do these changes affect neuronal firing and connectivity. We have a clue that it’s adding ‘noise’ to the system. Maybe things are attenuated or jumbled.”
These findings get us ever-closer to targeted molecular therapy for mental illness – much like is being done with cancer.
This is extremely hopeful.
Recently, an interviewer asked me if I thought bipolar would be cured in my lifetime. I said that it wouldn’t but that I wish it would.
Maybe I was wrong. Maybe these guys are onto something. Maybe molecular treatment will be available in my lifetime (or maybe not). Sure, that’s not exactly a “cure” per se, but it could be almost as good.
Additionally, knowing the “signature” in the brain for psychiatric disorders means that someday (maybe soon) we’ll be able to diagnose depression, bipolar, schizophrenia, autism, alcoholism and other mental illnesses by looking at the brain instead of only self-reported symptoms.
This is exciting and hopeful. I tell people there are scientific advances every day and that’s why none of us can give up, and this is just one example of how we can use what we know – these mental illnesses are genetic and overlap – to produce science that can help us all.