Showing posts with label genetic testing. Show all posts
Showing posts with label genetic testing. Show all posts

Wednesday, March 26, 2008

Genetic Testing for Bipolar: Are You Kidding Me?

Academics Dr. John Kelsoe and Kurt May have fired the warning shot: Genetic testing for mental disorders is on its way. Like much else in the mental health field, I fear that marketing may yet again trump science. Kelsoe and May's new test is out and it claims it can assess the risk for bipolar disorder (sort of) for a fee of $399.

Both Furious Seasons and Daniel Carlat have already opined wisely on the topic. The first issue is the science behind such testing -- if the science does not support the validity of the test in determining if someone actually has a mental disorder, then the test is a sham. So what does the science say? According to an article in Science, one genetic variant used in the test was associated with a tripling of risk for bipolar disorder. The catch: The variant was only found in 3% of individuals with bipolar disorder and 1% of the people without bipolar disorder. A genetic variant that is only possessed by 3% of people with bipolar can hardly be considered as widely useful. A combination of five variants in another study was found in 15% of individuals with bipolar disorder compared to 5% if those without the condition. As I understand it, the current test, as put forth by Kelsoe and May through the company Psynomics, tests for a combination of the previously mentioned variants. Again, the set of variants they are using are not very common even among people with bipolar disorder. So even if you are bipolar, the odds are high that this test would not label you as such. In the world of testing, this is called low sensitivity, which means that a test is nothing to cheer about.

Additionally, according to the Science piece, other researchers were unable to replicate Kelsoe's findings, making the test yet more questionable.

The thing about bipolar disorder is that it can be diagnosed by (drum roll please)... interviewing a patient thoroughly! That's right, a well-trained interviewer can simply ask questions to determine whether an individual has bipolar disorder. Imagine that. There is often a hullabaloo made over patients with bipolar disorder being initially misdiagnosed as depressed -- the way to solve this problem is not to perform a fairly useless genetic test, but rather to actually spend time with patients, perform a thorough assessment, and listen to them. How's that for a wild idea? If your response is: "But there's no time to actually talk with the patients," then no cookie for you! It is likely true that many people later diagnosed with bipolar were initially seen in primary care settings for a brief appointment, in which they were diagnosed as depressed (the underlying bipolar piece was missed). Again, giving a scientifically dubious test because "Gee, it's based on genetics so it has to be accurate" rather than training physicians to improve interviewing skills will only worsen the problem.

When I have more time emerges, I will post again on the topic. This idea of genetic testing for mental disorders certainly needs much more attention. When academics go into marketing, strange things can happen, as I have documented here on many occasions.