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Q: Blood Test to Help Diagnose Bipolar Disorder?
Dr. Phelps:
I read the news every day about the latest bipolar research. This past week,
there was a British study published that a blood test has been developed to help
diagnose bipolar disorder.
http://biz.yahoo.com/iw/070514/0252225.html
How credible is the science behind this study? Is the news media reporting this
research accurately? Do you think this kind of test is realistic? How soon do
you think something like this might make its way to America?
Many, many thanks for your book on BPII. It was a great help to me and has
helped my psychologist give me more accurate treatment.
Kind regards,
Dear Ms. B.--
Well, that is very interesting. Interesting, of
course, because anything which might help us with diagnosis would be of great
use; but also because of the way in which this information is presented in the
link you provided. As you are surely aware, this is a business notice, not a
presentation of a research finding in a scientific setting. And the company
which presents this news is doing so largely to trumpet their product. So, as
you have done, it is worth approaching all this with some skepticism (although
one could argue that such skepticism is warranted for any new research finding
even when it is presented in the scientific literature, as well).
Looking as closely as one can in this press release, it appears that the groups
which were compared were patients with schizophrenia, and patients with bipolar
disorder. The question they were asking was whether their new test can
distinguish these two patient groups from "controls", i.e. people who have
neither illness. It appears from the results they presented that this test may
indeed do so with relatively good accuracy. The "specificity" of 94% means that
when the patient really did not have the illness, the test was likely to say
they did not. Only 6% were "false positives". Conversely, the "sensitivity" of
78% means that when the patient really does have the illness, the test will
detect it 78% of the time; 12% of the time it will be missed.
Overall, these are fairly good numbers. The first thing we need now is a repeat
test-of-the-test by someone other than the company who made it. If the results
can be replicated by an independent set of researchers -- who are potentially
less likely to structure the analysis in such a way as to benefit the test --
this would be an important result. Let's keep our eyes open for that.
In the meantime, I will share one more reaction: I fear (though from this press
release is hard to know for sure) that this company may have taken the
preliminary results from research teams who have no commercial interests, and
turned it into a product. In other words, they may have been watching the
literature for indications that particular genes, or even particular chromosome
locations, were associated with either schizophrenia or bipolar disorder.
Without contributing to the further advance of our understanding in this area,
they may have cobbled together 28 genes that have significant promise for being
able to identify these disorders, and by putting them all together in a single
test, they have improved the statistical performance outlined above. If that is
all they have done, however, and if this was done solely with the intent of
making a lot of money, and if this was done to leap ahead of research teams
which are pressing ahead on trying to identify the actual genetic basis of these
illnesses; and finally, if in so doing they have robbed those research teams of
the opportunity to turn their own research into a marketable product, proceeds
from which could have been farmed back into further research on the illness (as
opposed to going into an investor's pocket), then I think their actions may
deserve to be condemned.
Obviously, there are many "ifs" in that last sentence. I just don't like finding
out about this through a company press release, instead of in a scientific
publication worthy authors are inviting replication before implying that they
have a tool ready for implementation. Just a little minor soapbox there.
Thank you for your comments about my book. I am very glad to hear that it has
been of use to you.
Dr. Phelps
Published July, 2007
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